I have stacks of regrets! DH asks me whether I'd change stuff though, and generally the answer is no. (Or yes, with lots of conditions, like that the future has to be exactly the same, but then it gets too confusing and I end up saying no.)
I love that from my mistakes I've learned lessons, had opportunities to change and grow, to deepen relationships, and lots more - but I still do regret every time I don't do what I know to be right or wise.
I don't think it's bad to acknowledge that, and I don't want to forget that regret entirely (although unhelpful dwelling is a different thing) - because remembering the past will help me to do better in my future. If I don't remember 'remember the time you made that mistake and how much you regret that' then I could easily make it again.