Not everyone thinks the way you think, know the things you know, believe the things you believe, nor acts the way you should act. Remember this and you will go a long way in getting along with people - Arthur Forman
I think I'm going to adopt it as my mantra. There's no point in worrying about what others are doing when I can't change it. Stressing over things outside of my control is not helpful so I'm trying to focus on myself instead.