Gonna play a little blog tag here. Carrie made a post about embracing regret. Gonch made a post about how he doesn't regret stuff. Both are interesting and valid points of view. I tend to agree more with Gonch though, and maybe not for the reasons you'd expect.
Yes, there's the point about how things today may be radically different if you could change the things you regret. For example, if I had not built up such a strong desire for an uber-serious relationship in college, I may not have had the series of epic love stories I've had in my life, and that would suck.
But the bigger point is that despite all of the hindsight and negative impacts of things I might otherwise regret, the truth is that I would've never learned anything if it weren't for those failures. I'm not sure if everyone rolls like that, but I'm pretty sure most people do.
I'm fond of giving younger friends advice about careers and relationships. Most of the time, they imply that I can go fuck myself by doing exactly the opposite of what I suggest, which is precisely what I would've done at the time. When you're vetting life, you have to see for yourself. That means you have to make a lot of poor decisions, like taking a shitty job for the money or getting into a relationship with extremely toxic elements, because you don't believe you're wrong. You have no data to indicate otherwise. You have to learn that for yourself.
One might argue that you live a life of suffering this way, but I think that's a little dramatic. I've had so much failure in my life that the successes are that much better. Failing spectacularly seems to lead to spectacular success.
I suppose the point is that I firmly believe the positives in life are born out of the regrets, so if that's the case, what point is there in regretting negative past events? You sure can't change them anyway. Three cheers for spectacular failure!