If you think God is merely something we worship to hide the fact that we worship ourselves then why God? Why does it take that shape?

What do the experts say?
C S Lewis said that if God is wish-fulfilment then the fact that this wish fulfilment is so common indicates that there probably is a God. He denies that wanting something to be true makes it true. But he denies that argument works in the case of God. He thinks God makes us need him to exist. But a God of wish-fulfilment is not a God. Plus most people in the world have other ways of dealing with their wishes. They may be content believing that the idol around the corner is their god. Most people are engaging in wish-fulfilment but the style of the wish-fulfilment differs from person to person. God is only one style. The need for wish-fulfilment then has nothing to do with God. It could be God or anything at all.
It is argued by some that even if God is a psychological projection, he can still be real. The two are not mutually exclusive. It is thought that God can use a projection to make himself known and create a relationship with the person. For example, you can want to believe in maths and want maths to be true. Thus it is a projection. But its being a projection does not make it untrue. We want maths to be true for we see we need it and cannot reason without it. The same cannot be said for God.
Freud believed faith in God was not just a projection of the desires and needs a person has, but also there was a reverse projection in the form of believers feeling they had turned their present bad situation on its head by turning to God.
Fromm argued that psychological projection was caused by a need to fit in with authority. It is about fear of the authority. Fromm saw projection not as paranoia but as masochism. God is authority. If Fromm is right, then because God is the ultimate and supreme authority, psychologically projecting a God must be maximal masochism. Maybe you have a sadistic streak which is why you want others to be masochistic too!
Feuerbach argued that many have a psychological need for belief in God and the afterlife and because of this dependency they accept belief in these things and in religion to deal with it. He believed that belief in God is a psychological projection, in other words, you need a friend and you make up one to fulfil this need. Hans Kung agrees with this (page 50, Eternal Life?). He says that if this is behind belief in God, it does not mean there is no God. True. But it means we worship an idol not the real God if there is one. Feuerbach's argument has been used by anti-religionists to demonstrate that religious faith is a neurosis or a delusion and dangerous.
Feuerbach said we worship God, who does not exist, because we want to express our dependence and helplessness. Against that Christians say, it could be insisted that unbelief in God could arise from our wish to be independent of God. Unbelief could be wish fulfilment too. True. But if unbelief is making a huge effort to be right then it is not wish-fulfilment. Believers assume God exists on paltry evidence or just because their parents told them he exists. That is wish-fulfilment.
Feuerbach held there was no God for God is just a psychological projection we use to get certain psychological benefits. He said this because he noticed that there are emotional reasons for believing in God. Against this it is said that if we are to be sceptical about anything people believe just because part of them believes it because they want to then we will believe nothing people say. But this is a misunderstanding. Feuerbach was not saying God is just a psychological projection because people want to believe. If they let themselves be guided by the evidence then he is not. He was saying that if the reasons for worshipping God are too emotional then God is a psychological projection. It is possible to have evidence for God and still worship him not because he exists but because you please yourself in doing so.
Suppose there is no evidence for psychological projection or against it. People have to tell us if they follow God for their feelings for because they have evidence of a relationship with him. But they are not going to admit it if it is psychological projection. Psychological projection would mean their worship of God is self-deception. The only sure way would be to observe how they claim to love and worship God and how they behave in a way that is inconsistent with that love. Most believers make little effort to promote God. They do not put him first. They may believe in fatalism and still act as if their fate is in their hands not God's.

Hans Kung said that atheism can be a psychological projection too. That is only true of people who for some reason don't want God to exist, perhaps they see God as a father-figure and they hated their own fathers. I would say he is right. But surely belief in God being a projection is more likely than acceptance of atheism?