Harley coming close to realizing Batman's motivation.
Catwoman: Do you really believe one man could take all that punishment?
Harley: Well, mayyyyybe. If he had a deep-seated trauma in his childhood or something.
After their run-in with Gaggy, Harley asks the others if she sounds that lost and needy when she talks about the Joker. She prefaces this by asking them to be honest. They don't disappoint.
Selina: Absolutely. Ivy: Totally. Jenna the Carpenter: I just met you and I'd have to say yes.
On that note, Jenna the Carpenter. She's a villainous carpenter, who, when she isn't planning bank heists or other nefarious deeds, makes her money doing legitimate carpentry work for various bad guys (at what are implied to be exorbitant prices). Not to mention the recurring real estate agent who specializes in themed villainous hideouts.