Do I have any regrets about my past? Most certainly NOT! In fact, I find my writing to be best when I'm in a deep mental state, and I find most best works written by 'sadistic' masochists, for example, Edgar Allen Poe (Who doesn't love POE?! xD).
I take my past as a great learned lesson (even when I didn't deserve the treatment) into forgiving those who have hurt me, and who will hurt me. Also, it's a way I portray in writing. And it's not just me, but it's every author out there. There's not one author who doesn't put at least one similar characteristic in one character in their books.
Most stories, you'll find they have happy endings, but there are some that will not, and there are depths of reasons as to why they don't.
Do I enjoy writing such stories? Call me crazy, or mental but definitely YES! And I love EVERY millisecond of it!
So this doesn't go just for me. It goes to every author out there that I know who'll agree with what I have to say, and feel like they're in a similar position <3.