I had a no-self experience, why is it a good state?

Self doctrine leads to craving [(Vicarita) Tanha Sutta], latent tendencies [Madhu,piṇḍika Sutta], pervertions [Vipallasa Sutta] and misery [Alagaddûpama Sutta].

Abandoning these negative states make one better as they would be replaced by positive states.

I think some people experience "states" as dukkha -- e.g. states are unpleasant ... or pleasant but impermanent ... or nice enough but not what you wanted.

So you get comments in the suttas like this,

But it’s only suffering that comes to be,
lasts a while, then disappears.
Naught but suffering comes to be,
naught but suffering ceases.

Or observations like "sabbe sankhara dukkha".

Also I think we're warned that people delight in or are attracted towards (intend to acquire) pleasant feelings, have aversion to unpleasant feeling, and (importantly) are ignorant in the event of neutral (neither-pleasant-nor-unpleasant) feelings.

So maybe it's a matter of developing wisdom towards "neutral" feelings.

For example there's a recommendation in this sutta about eating:

There is the case, sister, where a monk, considering it thoughtfully, takes food — not playfully, nor for intoxication, nor for putting on bulk, nor for beautification — but simply for the survival & continuance of this body, for ending its afflictions, for the support of the holy life, [thinking,]

'Thus will I destroy old feelings [of hunger] and not create new feelings [from overeating]. I will maintain myself, be blameless, & live in comfort.'

I think that's an example of a neutral feeling (or even "no feeling") being understood to be preferable -- with "feelings" being ultimately viewed as a burden.

I think a purpose of the "non-self" view is that any and every type of self-view is unsatisfactory too and results in suffering:

Bhikshus, you may well cling to the self-doctrine that would not cause sorrow, lamentation, pain, grief and despair to arise in one who clings to it. But do you see any such possession, bhikshus?”

“No, bhante.”

“Good, bhikshus. I, too, do not see any doctrine of self that would not arouse sorrow, lamentation, pain, grief and despair in one who clings to it.

According to this sutta, actual "joy" is instead associated with or resulting from a "lack of remorse" -- which comes from skilful "virtue" or ethics (i.e. "kusalāni" "sīlāni").

To get into samadhi, you do that:

"For a person endowed with virtue, consummate in virtue, there is no need for an act of will, 'May freedom from remorse arise in me.' It is in the nature of things that freedom from remorse arises in a person endowed with virtue, consummate in virtue.

"For a person free from remorse, there is no need for an act of will, 'May joy arise in me.' It is in the nature of things that joy arises in a person free from remorse.

"For a joyful person, there is no need for an act of will, 'May rapture arise in me.' It is in the nature of things that rapture arises in a joyful person.

"For a rapturous person, there is no need for an act of will, 'May my body be serene.' It is in the nature of things that a rapturous person grows serene in body.

"For a person serene in body, there is no need for an act of will, 'May I experience pleasure.' It is in the nature of things that a person serene in body experiences pleasure.

"For a person experiencing pleasure, there is no need for an act of will, 'May my mind grow concentrated.' It is in the nature of things that the mind of a person experiencing pleasure grows concentrated.

or even

Not content with those virtues pleasing to the noble ones, he exerts himself further in solitude by day or seclusion by night. For him, living thus heedfully, joy arises. In one who has joy, rapture arises. In one who has rapture, the body becomes serene. When the body is serene, one feels pleasure. Feeling pleasure, the mind becomes centered. When the mind is centered, phenomena become manifest. When phenomena are manifest, he is reckoned as one who dwells heedfully.

ie with this sutta https://www.accesstoinsight.org/tipitaka/sn/sn55/sn55.040.than.html, which means fewer objects cognized, then it is mano which has piti and the kaya has passambhati then sukhaṃ vediyati, and the citta has sukhha then samadhi.

If you did that, you did good.

The biggest problem people have is that

• first they think that any samadhi is good samadhi, but Ananda says the opposite https://www.accesstoinsight.org/tipitaka/mn/mn.108.than.html

• they confuse the proper way to judge their samadhi with some idiotic judgement about having thoughts or not, or being able to watch some kasina for several hours, or following some objects, like the breath, ''without distractions''.

The way to judge whether you had good satipatthana, good samadhi is with the ''abandonment of the defilements'', which are this stuf

3. "And what, monks, are the defilements of the mind?[2] (1) Covetousness and unrighteous greed are a defilement of the mind; (2) ill will is a defilement of the mind; (3) anger is a defilement of the mind; (4) hostility...(5) denigration...(6) domineering...(7) envy...(8) jealousy...(9) hypocrisy...(10) fraud...(11) obstinacy...(12) presumption...(13) conceit...(14) arrogance...(15) vanity...(16) negligence is a defilement of the mind.[3]

https://www.accesstoinsight.org/tipitaka/mn/mn.007.nypo.html

and knowing about it,

"In the same way, there are cases where a foolish, inexperienced, unskillful monk remains focused on the body in and of itself — ardent, alert, and mindful — putting aside greed and distress with reference to the world. As he remains thus focused on the body in and of itself, his mind does not become concentrated, his defilements [Comm: the five Hindrances] are not abandoned. He does not take note of that fact (does not pick up on that theme). He remains focused on feelings in and of themselves... the mind in and of itself... mental qualities in and of themselves — ardent, alert, and mindful — putting aside greed and distress with reference to the world. As he remains thus focused on mental qualities in and of themselves, his mind does not become concentrated, his defilements are not abandoned. He does not take note of that fact. As a result, he is not rewarded with a pleasant abiding here and now, nor with mindfulness and alertness. Why is that? Because the foolish, inexperienced, unskillful monk does not take note of his own mind (does not pick up on the theme of his own mind).

https://www.accesstoinsight.org/tipitaka/sn/sn47/sn47.008.than.html

not knowing whether the mind is defiled or not is the biggest mistake anybody can do (that plus saying that a defiled mind is not a defiled mind)

but when the defilements are indeed weakened, like above from MN7

10. "He knows: 'I have given up, renounced, let go, abandoned and relinquished [the defilements] in part'; and he gains enthusiasm for the goal, gains enthusiasm for the Dhamma, gains gladness connected with the Dhamma. When he is gladdened, joy is born in him; being joyous in mind, his body becomes tranquil; when his body is tranquil, he feels happiness; and the mind of him who is happy becomes concentrated.

• they also believe that they get the good satipatthana by sitting and ''watching the mind'' and doing nothing prior to that, whereas the good satipatthana and good samadhi is rooted in the " purified ethics and correct view." https://suttacentral.net/sn47.3/en/sujato

but people prefer to live their life which has nothing to do with the dhamma, then decide to meditate so they sit for 1h ''watching the mind'', then they get nowhere and they go back to their life which has nothing to do with the dhamma. When it comes to ''retreats'' they jump to the retreat from their life which has nothing to with the dhamma, they spend 13 days trying to purify their thoughts, and on the last they get some frail positive result. Then they go back home to live their life which has nothing to do with the dhamma and they notice they lose the few positive results they had on the retreat. Then they ask ''how do I get back the positive results I had in the retreat? I do not understand why when I meditate at home I do not get any result. please help me''.

Whereas the proper way to have good satipatthana and good samadhi is to filter the thoughts way before the ''formal sit'' so that when there is formal sitting, most of the thoughts are already good and there can be purification of vedana and sanna, ie piti and so on. Sitting is mostly for samadhi, with vitakka already mostly good, whereas sati sampajanna is done way before ''sitting''.

To get insights into the lack of self and the awfulness of craving, you have to know, see things the proper way:

Form, bhikkhus, is not-self. What is not-self is to be seen as it really is with right discernment thus: 'This is not mine, I am not this, this is not my self'. Feeling is not-self... Perception is not-self... Constructions are not-self... Consciousness is not-self. What is not-self is to be seen as it really is with right discernment thus: 'This is not mine, I am not this, this is not my self'. Seeing thus, an instructed noble disciple is disenchanted with Form, disenchanted with Feeling, disenchanted with Perception, disenchanted with Constructions, disenchanted with Consciousness. Being disenchanted, he is dispassionate. Through dispassion, he is liberated. With liberation, there is the knowledge: 'I am liberated.' He undersrands: 'Birth is destroyed, the brahmic life has been fulfilled, what had to be done has been done. There is nothing else for this world.'

https://www.buddha-vacana.org/misc.html

even with samadhi, just like it was done with satipatthana

‘The first absorption is a basis for ending the defilements.’ That’s what I said, but why did I say it? Take a mendicant who, quite secluded from sensual pleasures, secluded from unskillful qualities, enters and remains in the first absorption. They contemplate the phenomena there—included in form, feeling, perception, choices, and consciousness—as impermanent, as suffering, as diseased, as an abscess, as a dart, as misery, as an affliction, as alien, as falling apart, as empty, as not-self. They turn their mind away from those things, and apply it to the deathless: ‘This is peaceful; this is sublime—that is, the stilling of all activities, the letting go of all attachments, the ending of craving, fading away, cessation, extinguishment.’ Abiding in that they attain the ending of defilements. If they don’t attain the ending of defilements, with the ending of the five lower fetters they’re reborn spontaneously, because of their passion and love for that meditation. They are extinguished there, and are not liable to return from that world.

https://suttacentral.net/an9.36/en/sujato

What you experienced is the state of mushin or no-mind. It's actually exceptionally common to sort of fall into it accidentally upon waking. In Zen, we call this the silver valleys and iron cliffs of practice. Picture yourself walking among those metallic peaks and valleys. How does that feel? When you imagine yourself there, do those feature conjure a feeling of heaviness or fullness? Do they exude a kind weighty "something" within the context of your mind? Are they stark? Are you keenly aware of the lack of things on those metallic surfaces? Like there's nothing growing - no trees, no grass, etc? Is there a compelling blandness like the one that fills a house cleared of furniture? Is there an oppressiveness like that in a room full of steam heat? There is no happiness here, but nor is there sadness. The mind is full, but lacks everything.

The state of mushin is important, but it's not all there is. Instead, it's the state that allows you to access all of what comes next. Your mind is clear and everything else is cast aside. And it's from the perspective no-mind that real insight into no-self becomes possible.

I've found that in my meditation up till now there always was a sense of expectation from the moment, a kind of "if only I could be intense enough and concentrate, I will reach the state everyone is talking about".

Although this was very helpful motivation for me to investigate things and see the nature of suffering, this expectation is an illusion. Real happiness comes at the moment you don't expect anything from the moment. You just let things come and go without any expectation. When this is done and no thoughts interfere, you become content with just watching and being and a smile rises on your face :).

I tried it by repeating to myself "there's nothing better than right now", "this sensation is beautiful by itself" whenever a desire for something else arose. It was very easy for me to stay that way for a long period. Whenever a desire to run away and do something else came up, I simply reasserted this phrases and returned to the present.

I guess the work now is to deepen and integrate this state into daily life. Which shouldn't be very difficult because its pretty delightful.

If you ask me, I'd argue that "experiencing not-self" does not have to do that much with an specific feeling or sensation, but rather with a change in our paradigms, mental schemes and world-views. The internalization born from reflection, analysis and meditation allows the mind to change the way it interprets the world and sense-experience. You gradually stop identifying with things and states, and the possessive habit of seeing things as "mine" or "me" gets weaker and weaker in its influence over time.

The experiences you described might act as a guide to start to understand how the three characteristics (not-self, impermanence and unsatisfactoriness) are an intrinsic part of conditioned phenomena, but the goal of the Dhamma are not such experiences in themselves, because they are transcient in nature, just like any other feeling. When a sensation arises, one starts seeing it for what it is: just a sensation, with some specific conditions that made it arise in the first place, and which does not have anything to be called "I", "me" o "mine". These "unusual" experiences are something that might go as fast as it came, and so, getting attached to them or seeing them as an end in itself will only bring more insatisfaction.

The joy and peace arises naturally when the mind is free from pollutions, false expectations, anxiety and craving for conditioned and impermanent things. Life starts to feel good for what it is, and the habitual desire for controlling the world and its conditions gets substantially diminished with enough time and practice. Such peace and joy in the here-&-now is a different kind of peace and joy that the one we're used to, because it does not come from specific conditions, but from the wisdom the learns to let go a release the mind from attachments born out of ignorance.

Kind regards!