I turned 40 yesterday. Here are some lessons I've learned, without fluff or BS.

1) Stop waiting for exceptional things to just happen. They rarely do, and they can't be counted on. Greatness is cultivated; it's a gradual process and it won't come without effort.

2) Jealousy is a monster that destroys everything in it's path. It's absolutely useless, except to remind us there's a better way. We can't always control how we feel, but we can choose how we react to those feelings.

When I was younger, jealousy in relationships always led to shit turning out worse than it probably would have otherwise. Even when it was justified, even when a relationship was over, jealousy led me to burn bridges that I wished I hadn't.

3) College isn't for everyone, but you'll rarely be put square in the middle of so much potential experience. You'll meet people you probably wouldn't have otherwise, and as you eventually pursue your major, you'll get to know people who share your passions and dreams. Despite all the bullshit ways in which college sucks, it's still a pretty unique path on the way to adulthood. But on that note...

4) Learn to manage your money. It's way too easy to get into unsustainable debt. It only gets worse, and it makes everything harder. We don't always see the consequence of credit cards and loans when we're young, because the future seems so distant and undecided. But that debt isn't going anywhere... Try not to borrow money that you can't imagine yourself paying back now.

5) Floss every day, not just a couple times per week when you remember, or when you've got something stuck in your teeth. It matters, even if you're in your 20s and you've never had a cavity.

6) You'll always hear about living in the moment, seizing the day... It's tough to actually do. But there's something to be said for looking inward, and trying to recognize when too much of our attention is focused elsewhere. Constantly serving the future won't always pay off, at least not in the ways we think it will when we're young.

This sentiment doesn't have much value when it's put in abstract, existential terms, like it usually is. The best you can do is try to be aware of your own willingness and ability to be open to experiences. Think about ways in which you might be rejecting the here and now, even if it's as seemingly-benign as not going out with some friends because you just saw them, or you already went to that place they're going to. We won't recognize the good old days for what they were until they're already gone. The trick is having as many good days as possible.

7) Don't start smoking; you'll never quit as soon as you'll think you can. If you do start, make yourself quit after a couple years, no matter what. Keep your vices in check; drugs and alcohol in moderation. Use condoms, use birth control.

8) Don't make love wait. Tell your friends and family you love them often, and show them when you can. You're going to lose people, so it's important. Statistically, some of you will die young, yourselves.

When it comes to relationships, don't settle if you can't tell yourself you're in love, and totally believe it. Don't let complacency and familiarity get in the way of pursuing love. Don't be afraid to end relationships because they're comfortable, or because you've already invested so much into them.

Being young is a gift, and it won't last forever. You need to use that gift to experience all the love that you can, at least as a means to finding the person you really want to grow old with, if that's what you want. Regardless, you don't want to miss out on loving someone, and being loved, because of fear. Don't be reckless; just be honest with yourself.

9) Take care of your body. Neglecting it makes everything tougher. That doesn't mean you have to work out every day and eat like a nutritionist, but if you're overweight or you have health issues, do what you can to fix it. Losing weight isn't easy, but it's not as hard as people make it out to be. And it's one of the most important things you can do to invest in a healthy adulthood.

Don't put off nagging health issues because you think you'll be fine, or you don't think you'll be able to afford it, or you're scared of the outcome. There will always be options, until there aren't. Most people never get to the no-options part. Or, they get there because all the other options expired.

10) Few things will haunt you like regret. Making the wrong choice, for example, usually won't hurt as much. I guess you can regret making the wrong choice, but my deepest regrets come from inaction, complacency and indifference.

So how can we avoid regret? I don't know, lol. I don't think it's as simple as just commiting to choices... Choosing to do nothing is still a choice, after all. I think it's more about listening to your gut, as cliche as that sounds.

To thine own self be true, I guess. It's worth a shot, even if you fail. Almost anything is better than regret.

Anders Hjelsberg, creator of Turbo Pascal,C# and Typescript, three of my favorite languages.

Grace Hopper, fighting complacency and standing up for her self.

when u feel that u wrote some godlike code. 2 months later client wants to add new features. then u realize ur code needs major refactoring. "what was i thinking, far from godlike"