That's always been one of my favorite quotes.. mostly because I need to try harder at applying it to my life.

I think i finally figured out the way to deal with the ex:

Be happy. Be the happiest person alive. SO happy that you don't care if he's happy or not. This serves a purpose because 1. you'll be happy. 2. Whenever he sees you happy, sure he'll try to bring you down, but if you ignore him and continue being happy.. he always ends up giving in and being nice. stupid prick. Kill 'em with kindness.

Stay Focused. Just concentrate on what you need to do, and quit worrying about (as Ethan would put it) all of the background noise. That stuff is insignificant. and you'll be happier for staying focused and reaching your goals.