I find memory can be a beautiful thing yet a curse. It holds precious things from your past, victories, happiness, etc. But it can also hold your failures and things that have hurt you. Keep the good memories close and forget the bad ones.
It is a mental health disorder that is much more than being a "neat freak." Obsessive-Compulsive Disorder, OCD, is an anxiety disorder and is characterized by recurrent, unwanted thoughts (obsessions) and/or repetitive behaviors (compulsions).
"I think part of the reason why we hold on to something so tight is because we fear something so great won't happen twice." Sad thing is that holding on will also keep a greater thing from coming. Fear should never be a motivation.