Not quite 40 yet, but only a couple of years left.

1) Save your money. Yes partying with all your friends every night is awesome, but owning a house before you turn 50 is nice too.

2) If someone brings you down, annoys you, makes you sad ... ditch them. Don't waste effort on bad friends.

3) Don't overwork yourself. I wanted to be respected at work, to get promoted etc and I worked many extra hours, worked when I was sick etc... don't do it. You will burn yourself out and it probably won't do you any career favours anyway.

4) Eat well, take care of your body. When you get older, things don't work as well and you get sick more often, and you take longer to heal. Your metabolism will also change, if you were one of those people who could eat 2 pizzas and a few litres of Cola when you were 20 and never gain any weight ... be in for a surprise.

5) Try to enjoy yourself more often. Take time to do things that are just for you and make you happy

6) Try to have more meaningful relationships (as in don't chase tinder thots just after a fuck) but also with colleagues be more professional and engaging.

7) Think extremely carefully what you say. I've gotten myself into bother being a bit critical of a manager and my company. I lost one job because of it actually even though everything I said was 100% correct I mistakenly thought HR was there to help employees (they aren't they're there to protect the company) and most of them are backstabbing brainlets.