A lot of times, female characters - particularly the villains - come off as very one-dimensional. They get the short shrift in that they're only given the snappy comeback, or they're relegated to a very stereotypical role. I want to know what's driving them - that's what's really interesting.
In those times when a kid first tries to express themselves creatively, it sets them on a different path. Sometimes, that path can be really wonderful and can lead to a career doing some of the things you love. I also think that the price on that is a certain amount of alienation or distance created between a lot of the people around you.
When you're writing for a game - even if you're using very well known characters like Batman and his villains who lend themselves to many different interpretations - you have to keep in mind that you're writing for a different medium. Things are a bit more straightforward than it is for a feature film or a TV show.
The Joker is a tremendous vehicle for talented actors. Cesar Romero's was a bubbly, lunatic criminal. Nicholson did him as a vain, preening manipulator. Heath's performance of the Joker was remarkable, too. His was a low-simmering crazy street clown. Joker can be played all these ways, and they're all true.
I really didn't have any plan for her other than the henchgirl role, who was better at getting laughs out of the other gang members than the Joker was. I gave her the name Harley Quinn because I thought Harley was a fun name for a girl, and a lot of 'Batman' character names have a bit of a pun to them, like E Nygma.