*to bite the hand that feeds you* (Slang)

Definition: To be ungrateful; to turn against your family or employer or other supporters.

Example: 1) Always try to get along with your boss, and be careful not to bite the hand that feeds you.
2) Don’t bite the hand that feeds you – your parents may not be perfect, but without them you never would have gotten this far in life.

Etymology: ‘The hand that feeds you’ refers to the person who takes care of you, and to ‘bite’ or attack that person shows that you are ungrateful.