Hindsight is 20/20, as they say.
We asked Huffington Post editors what advice they would give to their teenage selves. From useful skills, to self-love and career advice, here are 31 nuggets of wisdom to learn before your teen years are over:
1. Learn a second, third, fourth language. They will open the doors to a new world and culture each time. It's also just easier to learn at a young age.
2. Take better care of your stuff.
3. Wait a day to write an angry letter (or email). More than half of the things I regret saying years later, I already regretted hours later.
4. Express those feelings of spontaneous affection and positivity whenever you feel them, even if you think you'll seem weird. You'll never regret being a little too nice.
5. Call your grandparents.
6. Learn what a 401k is.
7. Learn everything you can about personal finance. You'll thank yourself later.
8. Listen to your Latin teacher. Those seemingly obsolete words they're teaching you will come in handy on the SAT and for many years to come.
9. Internships are everything. Intern as much as possible -- it'll show you what you love and what you hate. Both are equally important.
10. Don't pledge to maintain friendships. You will grow apart from people you could have never imagined growing apart from. Give yourself permission to let each other go.
11. Romantic relationships aren't always the most important ones. Cherish the other relationships you have, too.
12. Be selfish sometimes. You don't exist to please other people.
13. You don't have to say "yes" to every invitation. Sometimes staying home and doing your own thing (or nothing at all) is glorious and well worth it.
14. Don't worry about "them," worry about you. It'll make all your relationships better if you know yourself well.
15. Try not to wear a statement piece on picture day. It won't be cool in 10 years.
16. Don't make unnecessary apologies. That said, definitely do apologize when you've done wrong.
17. Don't judge people too quickly. Just because they're different from you doesn't mean that your way of doing things is any better inherently.
18. People will try to make you feel like you're "supposed" to be doing things their way. Don't buy into that -- your only job is to be who you are, and like the things you like. If that bothers other people, then say "kbyeeee."
19. Look at the world with the curiosity of a child, and live fearlessly as if you have your entire life ahead of you. Do what you love even when it doesn't align with what you're "supposed to do."
20. Be spontaneous, and believe that you'll figure the rest out later. You've made it work every time before, haven't you?
21. Remember that confidence is sexier than anything else. But it's also OK to not feel confident or sexy some of the time. You're a human being.
22. Be your weird and awkward authentic self, and don't worry about it. You'll find your people.
23. Explore other cultures, to see the way other people do life. And if you don't feel like it, make yourself do it anyway.
24. Don't compare your inside to someone else's outside. Even the people that seem impossibly self-assured are probably dealing with the same doubts and insecurities that you are.
25. Try to be as self-aware as possible. Understand why you do the things you do.
26. If you don't ask for something, you won't get it.
27. Work hard. It's worth it.
28. Dancing like an idiot will ALWAYS feel better than dancing like a normal human.
29. As a teen, everyone is too concerned about what others are thinking to really have to time to think about anyone else anyway.
30. You are more than your reflection in the mirror.
31. Be kind. Always, always, always be kind.