Older readers (over 21), what is the best advice you would give someone younger?

I'm 26 and I would say that, well... everything will change. What is important today, what people you hang out with, what dreams you pursue, the things you like, the way you look at the world, the way the people around you act, your ideals, your knowledge. Nothing is a constant. Acting like something would be a constant will most certainly come and......   reply