Why did Buddha put so much emphasis on no-self?

I mean, everyone understand that no-self is truth but how can it help us remove our suffering..the only option i see is that you pretend that because things were no-self ,it changed..but ask yourself does this pretending ever help ...no.never.

Maybe because one's still "pretending" to see this truth instead of actually put in the time and effort to actually "live" it? What do you think the root cause to your envy/jealousy when your friend has a girlfriend ten times hotter than your own girlfriend; or s/he's ten times more wealthy, smarter, stronger, more beautiful; or when your teamate got promoted to managing director and became the boss of the boss of your boss; or your anger/resentment when you present your project to him, which you dedicated countless hours of work, including your own private time, and s/he simply said: "It's a piece of sh.."? the list goes on and on and on, but they all share the same kind of stuff, the "I", "mine", and "myself"!

When there is no self, there is no war since just because everyone has been fighting for their own goods. People in heaven knows to help, share with each other, hence they live there peacefully for a long time.
Greedy, hatred and ignorance/illusion are all because there is a self to bear. Until understanding there is no self, there won’t be any afflictions not pains. Is the arm, the teeth... mine? Think about what will happen if loosing them. They are not self. Just like the mother who don’t have self but their children. When people has no self but only others that they care about, they becomes Bodhisattva.

In my experience anyway, the idea of an absence of self as 'self importance' could seem completely crushing -- depending on how you look at it. From a quasi existential position, there may be some freedom to having a goal -- enlightenment -- that cannot ever be reached by me or you, is just about some impersonal causal series; or that may make it all seem quite disappointing.

No soul behind the scenes to suffer or be rewarded, only samsara and nirvana.

Anyway, without 'I and mine' you can imagine how greed and desire might be tempered; likewise hatred, its opposite. And if there really is no self, it makes sense that thinking there is multiplies all sorts of delusions and confused or foolish beliefs.

It Buddhist cosmology, soteriology etc. -- I mean the religion proper -- rebirth arises due to ignorance of how there is no "self" -- no unchanging substance making myself me, only a series of momentary causes and effects so that I am, like my experiences, completely contingent on past karma -- to be reborn

We are trapped in this vicious understanding of Self. I am superior , I am inferior , I am equal ... I did that ... I am doing this ..I will do that... The conceit and view of 'I AM ' runs our life. We are holding wrong view and this wrong view is pushing us into greater trouble forever. Therefore holding the right view and holding no conceit of 'I AM' takes away all your troubles and helps you achieve Nirvana. Thus it is of great great help.

Understanding No-Self helps us in great many number of ways. First and foremost it makes you dispassionate towards the five aggregates i.e. form, feelings, perceptions, choices and consciousness... Once dispassionate you escape from suffering !!! This theory is very much real. Try to put it in practice.

The doctrine of self varies in what is assumed to be true and what is taken to be a self.

The notion of self is a massive cause of psychosis. In dependence on it one thinks; 'i was, am or will be..', 'i am good because of this..', 'i am bad..', 'this is mine, may this be mine', 'this is my self, my self is good, is bad or may it be otherwise' etc

This idea is a ground for a lot of decision making. Ie one delineates other people as not self and one's own thinking & body as a self. One then might think; 'i am bad because of this painful circumstance, may i be in a pleasant circumstance, may my self thus become good, i will attain a pleasant state by causing grief to 'not self'.

Here it is basis for greed, ill-will & delusion. If the idea of self turns out to be a false delineation, empty in meaning, without a referent which can be established as a truth, then the whole line of reasoning leading to thoughts of ill will to another would turn out to be a tought of ill will in general in that it would have to be reconsidered as a baseless strategy for attaining happiness.

If there is no self then how would one treat good the elements which can be grasped by wrong view to be a self when one cultivates the element of cruelty towards other external elements which are otherwise identical to thr internal ones a body is a body, life-force is life-force, intellect is intellect, feeling is feeling; in the worst case it will turn out as a practical impossibility and element of cruelty will affect that which is taken to be personal as well, thus one might be harming oneself by harming others whilst cultivating elements of ill will, cruelty & delusion based on an untrue doctrine of a self; dwelling in wrong resolve & false expectations.

Furthermore if one treats oneself good by treating others good, thinking; 'my self is made good by making others good, i will remain like this'

This might turn out false, if that which is taken to be a self turns out to be not permanent then it will change or cease, a further effort needs then to be exerted for maintenance of a good state. One remains enchanted by good states, it becomes the resolve. Resolve on existence, pleasant feelings on one end, unpleasant feelings on another, neither pleasant nor unpleasant feelings in the middle.

Therefore the idea of self also ultimately blocks the resolve on knowing the unknown though liberation by wisdom based on disechantment; as it maintains the perception of existence being worthwhile there is then a lack of development of the intellect due to frequent giving of wrong attention and the nourishment of hindrances.

Well, it's not about the self existing or not existing, it's about taking this one thing to be all-important, important over everything and everyone else. And then all the suffering that everyone (including you, the thing) has to experience because you want this thing to live the longest and bestest life.

This is why it is emphasized, because undoing this illusion removes a large part of the problem that keeps perpetuating itself.

In scientific research on "Near Death Experiences" it is established that an individual who has had, say an experience, such as a near fatal motor accident, recalls the entire episode later after recovery in hospital. In this instance, the individual was able to cognize the entire episode from a detached "self". The doctors are often surprised that the individual recalls every detail from the time of the accident to the time of recovery in hospital. This shows that in this instance the ''self'' is detached from the body. At the point of our own death, when we leave our precious family and friends behind, this detached "self'' will still be operational but will not make a re-entry into the physical body as in the case of the motor accident victim. The Buddha explained that this ''self'' will be reborn in an infinite cycle of births and deaths. It is in this context that He said that there is no-self. His doctrinal message is that there is another "Self" which is of a permanent nature that is not subject to this infinite cycle. This other 'Self'' can be developed through a strict regimen of practices, which is the essence of His message. The discovery of this other "Self" is in the main, Experiential. The Reality of the other 'Self'' is a Universal Truth. The Buddha only showed "The Way."

The intellectual understanding of anatta is not particularly complicated, and i agree with you in that regard.

However, dhamma teaches us that intellectual reflection is one out of three types of wisdom:

• Learned panna (suta-maya-panna)
• Intellectual reflecting (cinta-maya-panna)
• Spiritual experiencing (bhavana-maya-panna)

And how is final knowledge achieved by gradual training, gradual practice, gradual progress? Here one who has faith in a teacher visits him; when he visits him, he pays respect to him; when he pays respect to him, he gives ear; one who gives ear hears the Dhamma; having heard the Dhamma, he memorises it; he examines the meaning of the teachings he has memorised; when he examines their meaning, he gains a reflective acceptance of those teachings; when he has gained a reflective acceptance of those teachings, zeal springs up in him; when zeal has sprung up, he applies his will; having applied his will, he scrutinises; having scrutinised, he strives; resolutely striving, he realises with the body the supreme truth and sees it by penetrating it with wisdom.

https://suttacentral.net/mn70/en/bodhi

This means that the road to enlightenment is not merely intellectual understanding. We also need the tacit knowledge of experiencing anatta directly, through the aid of sati and samadhi.

To use a metaphor: the instructions for learning to walk on a slack line is easy to understand. However, to learn how to walk the slack line we need the experience that comes from specific practice.

(On a side note, buddha never spoke about "no-self", but instead about not-self. There is a subtle but substantial difference between the two).

The answer to the question is the message of the Nakulapita Sutta.

Now, how is one afflicted in body & afflicted in mind?

He assumes [each of the five aggregates] to be the self, or the self as possessing [each aggregate], or [each aggregate] as in the self, or the self as in [each aggregate]. He is seized with the idea that 'I am [each aggregate]' or '[The aggregate] is mine.' As he is seized with these ideas, his [aggregate] changes & alters, and he falls into sorrow, lamentation, pain, distress, & despair over its change & alteration.

This, householder, is how one is afflicted in body and afflicted in mind.

And how is one afflicted in body but unafflicted in mind? There is the case where a well-instructed disciple of the noble ones — who has regard for noble ones, is well-versed & disciplined in their Dhamma; who has regard for men of integrity, is well-versed & disciplined in their Dhamma — does not assume [each aggregate] to be the self, or the self as possessing [each aggregate], or [each aggregate] as in the self, or the self as in [each aggregate]. He is not seized with the idea that 'I am [each aggregate]' or '[The aggregate] is mine.' As he is not seized with these ideas, his [aggregate] changes & alters, but he does not fall into sorrow, lamentation, pain, distress, or despair over its change & alteration.

This, householder, is how one is afflicted in body but unafflicted in mind."

That is what Ven. Sariputta said. Gratified, the householder Nakulapita delighted in Ven. Sariputta's words.

You're speaking of the self as if it is real. Only when you know it is not does the benefit of knowing otherwise become real. Being told the self is unreal will be of no help to you except as a clue. The idea is most definitely not to pretend anything.

You say 'Even if we do assume....' It would be an error to assume anything, and of no use at all. When you see beyond the self you wont be asking about the benefits but marveling at them. The theory is practically useless, the reality is all that counts.

You say everyone understands that no-self is truth but this is far from being the case. Even you seem to be questioning it. I'd guess 1 in 500 would be an optimistic estimate of how may people think non-self is truth, and those who know are even thinner on the ground. Most people wouldn't know what you're talking about.

The 'theory' of no-self is not designed to help us. It's not designed at all. It's just what is the case. It is not a theory for those who know but just the way things are.