But mentally... I'm haunted by almost every mistake I've ever made. Sometimes to the point of spending hours looking into ways to make sure it never happens again.
Especially now then I'm out of the big city and my life is 10x less exiting(More like 30x, actually). I wish I had done just a bit more, back when I was still doing stuff, not let myself get distracted by anything personal, and just generally appreciated things a bit more.
I was mostly generally fairly respected wherever I went, but every dev has times when they weren't at 100%, and really early on, when I was first starting, there were definitely a few days when I made pointless mistakes because my mind wasn't completely on my work.
But there really weren't that many of bugs per se.
The other big thing that haunts me are some of the personal projects I did, and the bad but workable decisions I made on early jobs due to NIH.
I still have a bunch of stuff in my parts bin that is almost trash. Several hundred dollars worth. I didn't really enjoy messing around with PICs all that much. I'm not convinced it was the most effective use of time career wise.
I don't know if I really benefitted that much from making a point and click game engine in VB.net.
I might have been happier if I had listened to people who said "Just use an Arduino" or "Don't waste your time even thinking of making GUI apps in C".