What are some things about adulting that you wish someone had told you in your teens?

This is a subreddit for people who are actively trying to be more of an adult. It can include tips, victories, and questions.

AITA for letting a kid I babysat draw on herself with a ballpoint pen?

A catharsis for the frustrated moral philosopher in all of us, and a place to finally find out if you were wrong in an argument that's been bothering you. Tell us about any non-violent conflict you have experienced; give us both sides of the story, and find out if you're right, or you're the asshole. See our ~~*Best Of*~~ "Most Controversial" at /r/AITAFiltered!