To thine own self be true

"To thine own self be true"

From Hamlet by William Shakespeare

These may be okay words to live by (although they're a little too easy to parody - see Jude Law dopily musing, "How am I not myself?" in "I Heart Huckabees"). Within the context of Shakespeare's Hamlet, they are meant ironically. They're uttered not by the play's noble (if indecisive) protagonist, but by Polonius, the resident hypocrite, who is not supposed to be taken seriously.