A Museum of Regrets

Whenever I have read an interview of some prominent man who says towards the end of his life that he has no regrets, he wouldn't change a thing, I have been puzzled. (It always seems to be a man who says that he has no regrets.) Did he ever play golf-- didn't he ever wish for a mulligan? Did he ever make investments? He couldn't have bought racehorses!

Didn't he ever regret saying something? Didn't he ever regret gratuitously hurting someone, whether he did it deliberately or inadvertently? Didn't he ever regret trusting or hiring someone? Didn't he ever regret not going to the doctor sooner or not insisting on more frequent colonoscopies than the guidelines recommend? Didn't he ever regret doing something that was self destructive?

I just don't get it. How does one mature and learn to be a better person without regrets? 

An expression that has always made sense to me is, "Life is a museum of regrets."