**WARNING. POTENTIALLY NSFW.**
Now, with that out of the way:
What excites you about the opposite sex? A way they move, they smell? Perhaps a certain physical attribute, or even a mental attribute? A hobby, maybe?
What turns you on?
Inversely, what turns you off? What's something that, no matter how good-looking or "amazing" a person might be, they do or have something that just seals the deal of "No" for you?