@sim 
Depends on the specific circumstance.

Usually not, least for me. Tends to leave me in a state of regret, and we can't change what's in the past so. 

On the other hand, as cliche as it sounds, it's possible to learn and grow from even the most awful of experiences. 

The problem with the latter is that it takes a -lot- of work, and it'll still hurt revisiting the thoughts.