People want different things. Even if two perfectly rational people agree on a shared model of reality, they still might not agree on what actions to take as a matter of aesthetic preference.

That said, it's true that few are rational and honest. Everyone wants their ideals to be reality, but most people confuse their ideals with reality itself. Even those who can tell the difference may choose to trick others into delusion, so that they may use them for their own benefit.

I used to do that, but not so much now. Being honest with myself and the world is a more interesting way to live.