One of the most often quoted quotations, and one of the most severely misunderstood, goes as follows:

This above all, to thine own self be true, …

This is routinely attributed to Shakespeare, and of course that is not completely wrong. Shakespeare did indeed write this line. But what is routinely forgotten is that these words were written by Shakespeare, yes, but spoken by Polonius, a character in a play (Hamlet) which involves a lot of extremely unpleasant people, Polonius being one of the more repellent among them. Polonius is a conniving, deceitful, duplicitous, pompous, court creature. All of which makes the next bit of that quote (from Act I scene iii, if you doubt me) especially ironic:

… And it must follow, as the night the day,
Thou canst not then be false to any man.

It doesn't follow at all, of course. Being "true to yourself" is a classic excuse for telling lies to other people.