Every loss teaches us something, so I try not to forget at all.
That must be a large brain retention ability, all my losses in gambling is way too much to be able to think about them all, only new gamblers can do this, there are some losses that I can forget because of the circumstance around them and some were the events of the game, but a usual gambler can not keep all of their losses in their head. I just try to forget my loss and a win helps me do that.