Resentment is like drinking poison and waiting for the other person to die.The Quotations Page
US author & movie actress (1956 - )
I would suggest that merely resenting something is not necessarily harmful, as long as one does not wallow in resentment. "I resent that remark" is one thing, understandable and even healthy, depending upon circumstances.
But resentment is often a cover for envy or hatred, which are different matters entirely.