"I don't think you should brood on the past and let it keep you from getting on with life in the present. But I do think there's benefit in reviewing past events from time to time, and evaluating them so you see how you may have made mistakes in certain situations and avoid doing that in the future. And you can be better prepared if you notice situations in the past that are similar to what's going on around you today," Violet added aloud.

Such as weird things going on at Hogwarts that start out as nuisances but later turn out to be dangerous (yes, vines, I'm thinking about you). But no one at school ever seemed to learn from the past in these cases.