You are, if you are a young person, going to spend an inordinate amount of time worrying about what people think of you. And actually, if you're an old person, too. You'll worry for hours and days about what teachers and peers and bosses and coworkers think about you when you won't talk to them in a year or two after you're done with school or that job.
You'll pass on things that might be "too embarrassing" even if it's something you really want to see or do, you'll worry about what people will think if you did something, you'll hold off on doing something you really want to do because someone or someones might not approve, you won't talk to that girl or that boy because you worry what everyone will think if you get shot down, you will be terrified of mistakes you made that everyone saw and obviously remembered.
Only, they don't. First off, most of the people you're worried about watching you won't even remember you were there 10 seconds afterwards. If you flame out spectacularly, people that were there might remember for a while, but they'll probably forget in the minutes, hours, or days afterwards. And if you really, really screw up, it might become a funny story they bring up to get laughs, but even then, they'll forget or they'll die and it will be like it never happened.
So the great irony is all those things you spend so much time worrying about and all that approval you crave from anonymous people will eventually fade away and be forgotten in the seconds, minutes, days, months, and years afterwards, even if it's something really, really spectacular, good or bad.
Unless you're Hitler. People remember Hitler.