Mine would be ‘Pay attention to everything and judge for yourself whether it applies to you or not.’
Don’t marry her, she ain’t worth it!
Forget the humanities! Go into law, medicine, business, science!
Write!
At least try pot once!
Visit a competent doctor
I wouldn’t tell my teenage self a thing.
What would the point be? I’m quite happy with my life as it is now.
If I were to go back and tell my teenage self something that made him do anything differently, do I-as-I’ve-become even exist anymore, ever come to be? Or does a second timeline open up, where I keep on being who I am, but a clone of my teenage self goes off in another direction on another timeline, becoming someone different than the person I am now?
I think I’ll just leave spacetime as it is, thanks. 
Yes, those first few pounds matter.
Yes. 
No seriously, I’d tell myself to set boundaries with my mother and keep them. I’m 46 years old and still dealing with the repercussions.
Stop fretting over what you’re not. Focus on what you are.
Go for it.
Take things much more seriously. Work harder. Opportunity rarely knocks twice.
Believe in yourself
Try to improve your social skills, even if it does scare you at first.
You are not depressed because you need Jesus or because you don’t think positive. People who tell you that are idiots. There is something wrong and you need to see a doctor as soon as you can.
The Humanities are great but try learning a few useful skills like typing or bookkeeping. Contrary to popular belief they do not destroy your creativity and you just may need them.
Jimmy Page does NOT worship the devil. Worry about something else.
Yes, Ellen probably wants to go out with you. And maybe one of the twins; I think it’s Kathy, though they’ve lived down the block for years and you still can’t tell them apart. You aren’t really as unattractive as you think you are. There’s a reason you keep falling asleep in Anthro class, so you probably shouldn’t major in it in college. And learn to type, ferchrissake. Trust me, it will be important in just a few years.
Think again about Nursing.
Marry that rich girl who was crushing on you.
This. And its companion piece of advice: Being smart isn’t enough by itself.
Sometimes you gotta take the pussy like Pepe.
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