It's about time we got Harley Quinn on film, and you can't have Harley without The Joker. The dastardly duo's tumultuous relationship has been a highlight of comics and cartoons for years, but we still haven't gotten to see them in the flesh outside of every third cosplayer at a comic book convention. Though both of them are essentially murder clowns, it's likely that pair will provide moments of levity in the middle of what's become Warner/DC's trademark gritty tone.
Harley and her Puddin' are a lot like a bouncy castle filled with light bulbs -- they're a lot of fun, but you've definitely got to watch your step. The Joker is more or less the world's worst boyfriend, and has proven himself to be verbally and emotionally abusive on several occasions. But however nasty the Joker gets, Harley feels drawn to and maybe trapped by him. It's an exaggerated reflection of real dysfunctional relationships, but it'll take a lot of tact to portray that without making both Harley and The Joker pathetic or unlikable characters. Maybe Harley's arc will involve her growing out of The Joker to become her own person. Maybe she'll realize that she can never truly be with The Joker because he's in love with Batman. Or maybe it will be an awful live-action version of this:
Either way, I think we can all agree we're curious to see the footage from the camera mounted in that bouncy castle.