And sure, the answers I tend to give out mirror those of my peers: because it's a way for me to express myself, capture the dynamism of beauty in one static frame, freeze the one perfect moment of everyday life... But looking deep into myself, I think it's the ability to create something that interacts with the viewer. I suppose it stems from my design background. In my professional life, each day I design communication that's geared to interact with and involve the audience.
Of course, the stuff I do at work is usually a blend of copy and graphics, which when fused together make the interaction easier, but the principles remain the same. I tend to apply these same principles to my paintings. And what are these principles? Well, the basic tenet is "Suggestion through Omission". For instance, sometimes a semi-clad body can be more erotic than a full nude. The mechanics of looking for, or mentally filling in, the missing pieces force the viewer to be an active part of the art.
Do let me know how successful (or not) I've been.