I should not get angry when other people blithely ignore how easy their life is, because it was my habit, once.
I should get angry when my friends treat each other like untrustworthy strangers, because they're being selfish.
I should not get angry when my friends insist that they miss me, but never call, since I rarely call other people, since I figure "why bother? They don't care".
I should not get angry when my friends trample all over my generosity and goodwill like wild animals, because my personality encourages it.
When I'm in a bad mood, I should stop keeping it to myself, since everybody else I know certainly doesn't.