Sort of an off-shoot from the books thread.
Off the top of my head:
1) no-one really gives a shit about what you look like/are wearing, and if they do, they are tossers anyway.
2) Failing at stuff, relationships included, is fine, things get better.
3) Pick the thing you love and do it every single day, that is how things get done. You were right when you were 15, the following 5 years of 'getting real'' was limiting bullshit.