Very early on, Lydia knew that she couldn't compare her neglectful parents to anyone else. It wasn't really fair, and she didn't know the whole story. However she could commiserate with the fact that parents were generally awful. They both had scars now. Of course hers was from a werewolf.
"That makes sense. I don't think about it that much either. At least I didn't until recently." Wandering through the woods naked tended to give you perspective.