I only recently became aware that psychologists have a label for this phenomena, where people feel a vague sense of shame about themselves.
Psychologists couch it for specific circumstances. For example, it’s the small insecurity that many feel about their competency in a job, or adequacy in a relationship, as in “I’m not good enough and people will find out..”–kind of thing.
But I see it more broadly. The small feeling of doubt or shame that you feel comes from the feeling that you are not who present yourself as, and there is the fear that you will be found out.
It’s not a delusion. It’s real. Because you really are not who you think you are. You’re not the ego.