At 40+ you realize you've pretty much accomplished everything you're going to with your life. All those plans and ambitions? You've had 40 years to act, if you haven't done something yet, chances are you're not going to. Its all down hill from there. Hopefully you've got a family you can put you're energy into. At least this was how i felt 40+, ymmv.

How depressing! I'm 37 and still feel I've got loads to learn and try out. Although I note that many of my peers are planning their escape routes to retirement.

If I try to create a startup I'll be doing it on my own.

Thanks for the down votes, guess it's wasn't obvious enough I posted my personal experience, was the ymmv (your mileage may vary) at the end not enough?

I think you might be suffering from the current "downvote mania that we're not allowed to talk about or else you'll get downvoted" on HN.

EDIT: I disagreed with you, with a following comment, and didn't downvote you.

It may be because you used "you" 10 times and "I" once. Given that, it's clearly not obvious.

You're still alive, right?

I'm not 40 yet, I'm 29, but I feel like I've only had 9 years to act so far and I have another 30-40. Look at how old Elon Musk is and he's finally hitting his stride. Still got time man.

He's 43, but your comment makes it sound you think he's older.

I'm not sure he's a great example. He has inertia and a lot of money made from when he was much younger. Take an average person at that age, middle class income, family, etc, and see if they can accomplish life changing goals that they just started chasing.

I'm not going to agree with the poster above that claimed that "At 40+ you realize you've pretty much accomplished everything you're going to with your life." but I think as a generalization it's probably closer to truth than feels comfortable (I'm 37).