I shouldn't have eaten that whole cake.
You shouldn't have lied to your parents.
They shouldn't have spent all their money on vacations.
We shouldn't have skipped class today.
He shouldn't have ignored her messages.
She shouldn't have quit her job without a backup plan.
You shouldn't have broken your promise to help me.
The company shouldn't have ignored customer complaints.
They shouldn't have cheated on the exam.
I shouldn't have procrastinated on my assignments.