My regrets in life are very, very, few; but those few have been so serious and deeply felt that I don't let myself think of them, can't put them into words, and won't put them on the Internet.
Still, when I've asked myself what I could have done to have prevented them; the answer in most cases has been, "nothing".
I wish things could be as simple as imagining going back in time and at least imagining how things could have been done differently, and turned out better; but they aren't.
When we're looking ahead at time, we usually feel confident that we'll make all the right choices. When we're looking back on it, we can tend to wonder what happened that led to our making some wrong ones. When all is said and done, we make our choices based on the information, knowledge, and experience we have on any "today"; and we learn how to work with the consequences of yesterdays, and preserve that confidence that comes with looking ahead at tomorrows.