One is that everyone is human and capable of whatever another human does or did, with the right effort.
Because everyone is human, no matter where you are and who you're talking to, they want pretty much the same things in life. While people are special in the way they behave, deep inside they aren't magically entirely different than anyone else is.
Three is that life is like a game. You're going to be dead, and things you did wrong won't matter. Heck even looking back you're going to enjoy the things you did, not that you didn't do, or mistakes you made - you're not going to care about those (unless you were totally reckless of course).
Probably there's a bunch of other good advice, but these perspectives surely help with living a fulfilling life.