A case study in abusive relationships and how women (and even some men) justify staying in them: the Joker and Harley Quinn. I just finished watching the episiode entitled “Mad Love” from the (old) new Batman-Superman adventures series (not to be confused with Batman: The Animated Series). Long story short, even after Joker throws her through a window, Harley Quinn laments, as she falls several stories, that it’s her fault because she didn’t get the joke. If that’s not denial, I don’t know what is.
(There’s also a weird undercurrent of kinky sexuality involving whoopee cushions and the like ever since they introduced Harley Quinn into the Batman universe, especially in the animated series, but that’s a whole other issue.)