What's something that turns you on, but isn't necessarily sexual itself?

I, for example, am very turned on by contrasts. So noticeable height differences, size differences (individual body parts or the whole package), skin tone, shapes, etc.

I kinda wish my wife (who's very pale) were bi because I would love to see her have sex with a dark skinned woman that's a similar height and weight as her, or a short, petite woman (she's also tall for a woman).