why do people allow themselves to believe the world revolves around them?

Because they don't "allow themselves"; someone else allows them to believe it. The alternative to allowing it is that the relationship may have to end.

The Devil hates the mirror - The spiritual mirror that reflects the rich darkling thoughts and machinations of our monstrous Ego. (Mentality and spirituality being fused, some say this is to be in the world and of the world, a much less spiritual realm)

The Ego in Hinduism is the false self.

Often when we judge or philosophize with the words we mindfully construe (dualistically constructed), we actually tell others where we are. (This is not something we're always consciously aware of especially when pointing fingers, or when trying to conquer this lunatic asylum)

Also, that which we dislike or fear about ourselves we often resent and/or try to change in others – Insecurity - To judge others by our own standards - To accept them as normal as long as they think and behave like we do – (To use reassuring proverbs, self serving mantra's and rich figurative speech, or be duplicitous by suggestively supplanting even in order to convince and subdue while circumscribing minds), To be rich - The traits of Egoism - To resent the truth - (And is why we claim the stage which can also be used to demonize others in an attempt to paint ourselves whiter than white) - To claim the efforts and works of others as our own, either directly or by mendacious and surreptitious association (spurious claims)

There are those of us who earn the stage and those of us who claim the stage - We don't need an audience to tell the truth, but we do need an audience to lie.

Even when we know we are wrong or have done wrong, we will unconsciously entice/antagonise that which we have capitulated to in others, this is because the blind/monster within seeks to justify and gratify, is inclined to rejoice which is to gain deranged self gratification and even revels in it's own perversion – The Monster comes in it's own image and constantly seeks to reassure it's mirror image by projecting it's own issues with conscience onto others, (The bully blames the victim, but really wants to entangle and embroil others), as it continues to write it's own book.

Die to their ego.

Pretty easy to figure out if you consider what you're asking here.