Do the best that you can until you know better. 
Then, when you know better, do better.

~ Maya Angelou

A little comedian wisdom

(Chris ) Rock's set is surprisingly pro-bully; his reasoning is that being bullied toughens you up and gets you ready for the real world, which is filled with assholes.

~ Rolling Stone, on comedian Chris Rock

Ancient wisdom about when to give up on an argument

If a man objects to truths that are all too evident, it is no easy task finding arguments that will change his mind. This is proof neither of his own strength nor of his teacher’s weakness. When someone caught in an argument hardens to stone, there is just no more reasoning with them. 

~ Epictetus - Discourses I, 5.1