While Batman and Harley Quinn is geared mostly towards comedy, there are some heartwarming moments:
- While it also counts as awesome (and even tearjerking to a certain extent), it's great to see that Harley really has turned over a new leaf and is doing her best to live a "normal" life.
- As Dr. Goldblum is dying, Harley shows what a good person she can be, comforting the scientist in his last moments—she even tells him to meet up with her grandmother when he gets to heaven, feeling that the two would hit it off.
- When Batman attempts to kick Harley off the team before going to Louisiana and upsets her in doing so, Nightwing is noticeably sympathetic towards her.
- Harley Quinn ultimately convinces Poison Ivy to turn against Floronic Man's plans to turn the humans and animals of Earth into plant hybrids through a combination of Puppy-Dog Eyes and Cry Cute—while Poison Ivy may be a criminal and an eco-extremist, she doesn't want to risk the lives of billions upon billions of people (including herself and her best friend).
- The dynamic duo kisses Harley Quinn on her cheeks (at the same time) after she comes up with the plan to defeat Floronic Man once and for all (she suggests simply setting him on fire since he's made out of plants).
- Whether or not this movie is part of the DCAU, it's really cool to see Batman and Nightwing working together like they did when Nightwing was still Robin, with no indications of Teeth-Clenched Teamwork like in TNBA.
- The movie's very existence indicates the long-awaited return of the DC Animated Universe after eleven years and it is heartwarming itself for any adult viewer who grew up with the animation franchise since they were kids.