Why can't the past just stay in the past?

Good Morning.

Short post in connection with the random thoughts the flood my head this morning and, I'll warn you now, it probably won't make much sense

Everyone has done stuff in the past they regret right? And, surely, sometimes you look back and you can remember periods in your life where you were simply not happy? So ....  you do what needs to be done, no matter how difficult that is,  and move forward/change the situation and this in turn makes you a stronger person and, in my opinion, changes you for the better.

So, pray tell, why does that past, which you want to forget about and move forward from, have a nasty habit of coming back and biting you on the ass? Why can't the past just stay well and truely buried six feet under in the ground where it bloody well belongs! Or is that too much to ask?

From recent experiences, I believe that I am a much stronger person, my outlook has changed and for the first time ever .... I feel content and at ease. But then, all of a sudden the past rears it ugly head and it throws me off balance and takes me back to a time when I wasn't very happy nor was I happy in myself! DAMN - I don't want to be in that place!

So, I will try my damn hardest to detach and leave the past exactly where it should be ... in the past. Easier said than done though I think!