Earlier quoted context omitted.
I feel like people often regret not taking the risk to go work (hard) on something they find meaningful. Not sure if as many regret that they didn't put in the extra hours to get to the next level in a big corporation.
I think there are people who do regret not getting to the next big level. They thought they could have been a good (software) architect or director or principal, they thought they could have really made some lasting difference, but instead they were a cog their whole lives. Success is important, feeling successful is important. It can be hard to be happy with "good enough".
http://www.paulgraham.com/hamming.html
Just read it for the first time yesterday and plan on doing so many more times in the future.