Regrets? I've had a few; but, then again, too few to mention.
I could regret having voluntarily foregone a normal childhood in favor of solitary intellectual and artistic pursuits, but then I wouldn't have had the foundation that later allowed my to do some really neat things for a living.
I could regret having dropped out of high school upon learning that I'd won enough in scholarships to attend Waterloo at a tidy profit just before graduation, but I'd probably be complaining about the idiots I have to lecture when I'm rudely dragged away from my hunt for a generalized solution to the n-sphere packing problem (which will, of course, be crucial to the moving industry when humanity evolves beyond the constraints of three-dimensional meatspace).
I could regret the ethical quagmire that was my military service, particularly around the time of the Oka crisis in Quebec, but I would have to do without the discovery that I am a rather good teacher of matters mathematical and technical, and that I can speak publicly with confidence about things that matter to me.
I could regret drinking myself half to death trying to solve the question of how to appear to be social while remaining comfortable in my solitude, but without a truly desperate need to save my life, I never would have been able to overcome the voluntary, learned autism I developed in childhood.
As jacobroufa said in an earlier comment, if I were to change any of that, I wouldn't be who I am today. And I have had a life that is nearly beyond imagining. I'm a high school dropout (I never did finish, or even get a GED) who has taught electricty/electronics and mathematics at college. I'm a "failed" musician (I sold six records -- not six different albums; six paid-for copies of my one and only album) who, as a utility sideman, played gigs with some of my heroes in the jazz and blues world. When educational funding dried up in Ontario during the '90s recession, I found that the only postion available for an ex-military high school dropout was shining shoes, and that drove me to but an obsolete computer and teach myself to program. It took a while (years) to meet my own admittedly high standards and to break into the industry at all as a n00b pushing forty, but I became a highly Googleable entity (once you figure out how to filter out the dead folk singer with whom I share a name) and had a reputation for innovative thinking within my little niche (Notes and Domino -- please hold the comments; the platform is much better than most of the applications written for it). No shoeshine boy, no Google hits. I've loved and been loved in return; I've had my heart broken and experienced loss -- and become more human in the process. I have a tremor disorder with an associated dementia now (and hang around places like this and Stack Overflow to stave off the decline as long as I can -- it beats doing the crossword), and suffer intermittent aphasia that sort of alternates between Broca- and Wernicke-associated damage patterns and am hugely unreliable due to physical incapacitation, yet I'm still asked to give motivational talks on a regular basis. (Yes, by people who have heard me before.)
We can spend a lifetime regretting the path not taken, and another worrying about the consequences of the next choice. But always keep in mind the sage advice of Yogi Berra: when you come to a fork in the road, take it. Read as a mere Yogism, it may seem inane, but if you really give it some consideration (as Yogi did before he said it) you'll find that it is an admonition to avoid the paralysis of indecision. There may come a time when you wonder what might have been down the other path, but standing at the point of choice, tossing coins for the rest of your life means going nowhere and doing and learning nothing.