10 Worst Things Harley Quinn Has Done To The Joker
5. Going On A Date With Batman - Harley Quinn Valentine's Day Special
In a wonderful twist of fate, one of the best insults to the Joker is one that neither him nor Harley are aware of. Given that Harley has canonically been on two dates with Bruce Wayne, she has technically dated Batman - albeit without realising.
But as a reader, you can still get a strange sense of satisfaction out of knowing that the Joker's former partner managed to go on to date his worst enemy. In fact, it might actively be funnier that Harley doesn't actually know, as she hasn't actively sought out Batman's alter ego, but rather they've been brought together by fate.
In short, it is basically a cosmic justice that Harley and Bats have dated in the past - even if Bruce definitely felt pretty weird about it at the time.