Never had it happen where I lived with regret not related to decisions with consequences. Like failing the drug test at MEPS for Naval Enlistment when I was 19. I do regret it because I was going to have a really cool MOS that they push on people what decimate the ASVAB.
Its not worth speculating, but if I stayed that course I would be almost 20 years in.
There are some interpersonal failures to get laid where lack of "game" or "being a pussy" lost out on sexual gratification, but those are meant to teach.
**** Insert semi-lucid anecdote ****
Bizarrely, I have had ideas of love get pushed my way. Somewhat annoying situations where I had to trust that "someone" (some bitch) loved me. If only I just had hope of being with this mystery woman. Might as well trust Sin Jones.
I remember my criticism being, "Who the fuck turns love into a work retreat exercise? Last time I checked offers like that are done directly and in person. Not made into agitating traps of gullibility. Ambiguity is the father of the gaslight, you know."
I have the opposite of regret on that because it is enjoyable for me to mock it. The offer was invalid and can remain "could have been" indefinitely for failing to have a material existence in my life, which most certainly matters to anyone not operating on stalker logic.
Hope that answers your random question.