I do not know how to regret what was and has passed. I can somehow relate to the past, good or bad, but regret is stupid. Regret is not constructive, out of a feeling of regret it is impossible to create anything useful. It is necessary to treat the past with gratitude, because it gave me certain experience, from which I am learning lessons and draw conclusions. Even if the experience is very bitter and difficult, you still learn a lesson from it, you become smarter, and for that many thanks to him.