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.
And it's true, winning significantly helps to forget losses. Typically, people only remember a few of them, the first seemingly dramatic loss and major losses. If someone talks too often about their gambling experiences to others, whether it's about losses or wins, it will certainly make it difficult for them to forget. This heavily depends on a person character, and in my opinion, it's better not to share much about gambling experiences with others.
Instead of remembering losses, I believe many people are more inclined to remember wins, especially wins at specific moments, regardless of the amount for instance, when they desperately needed money. However, both losses and wins can push someone into gambling addiction. Those who lose tend to want to chase their losses, while winners also tend to become hooked.
Most people are actively suppressing memories of losses to preserve their ego regardless of how much they are winning. This is a sign of weakness of character. Instead of bravely admitting their mistakes, they run away from them like little children and try to hide that they did something wrong. This is actually one of the main reasons why gamblers continue to repeat the same mistakes, besides compulsion that is created by addiction. Unless you are able to bravely admit that you did something wrong then you can't learn anything from it.