I think the type the things i learn from the past are things that i either enjoyed and loved or did something bad. You always learn from your mistakes to make yourself only a better person. It helps you in the future to remember the things you did bad and not want to go through the experience again.
When i forget the past it's usually something that i dont like to talk about because it was a bad or annoying or etc. It helps to forget about something so then you dont even remember it happened. But it all depends on what happened.
So i think either way i forget and learn in my life. It can go both ways in my life, and it has always been this way, and will continue to.