Belief about "what one should be?
This makes no sense.
Its unjustifiable.
There's no 'because'
Like this:
I should be still ovulating in my late forties, because I am a biological female with ovaries, and most but not all females of my age still ovulate. However my ovaries failed early therefore I am an atypical member of my sex, which is female.
Should be is a concept that relates to what one is and what one might realistically be.
"I should be Hillary Clinton/have three legs/be a different species". These are nonsense, fantasy, impossible claims. No one should respect such claims.
"I should be X", needs a "because Y" to follow. People will then assess the "because Y" to see if it sensibly justifies the belief, or if it's a delusional belief, or false reasoning.
If someone cannot provide a "because" it's because they do not understand or acknowledge the nature of X and how it relates to themselves.