Should
Criticism of the past action
I should have prepared more to not fail the test.
Picture of criticism of the past action
Regret
Picture of regret
I was eating in the restaurant. I should have ordered ice-cream too.
Advice
Picture of advice
Your hair is too long. You should get a haircut.
Moral obligation
You should never lie to your parents.
Picture of moral obligation
Disapproval
She shouldnt have dyed her hair in bright colour, because she is in her forty.
Picture of disapproval
Reproach
She should have done it better.