What is he thinking (and smiling) when he's looking at
2) teeth (when there's nothing on it)
Why do guys look at certain features such lips stead of eyes?
Most Helpful Guy
Most guys enjoy seeing all of those parts, because they are all pieces that can make someone attractive, or in some cases, unattractive. Then you have to understand that different guys have preferences for different things. Some guys are "ass men" and they love how her ass is shaped, how it moves, how it feels, etc. Some guys are "breast men" and they love everything about boobs. Some guys are leg men, or feet men. And most any guy loves a pretty face and nice hair.
For most of those items, guys are mostly just thinking "I like that. It's attractive. Yummy." If it's their "main" attraction item (boobs, ass, legs, etc.), they might be picturing you naked, and imagining what they look like naked (this is pretty common). On occasion, they might go so far as to imagine you having sex with them, but that's actually the exception rather than the rule.
Remember that men are visual; we evolved to be able to find healthy (this is reflected in things like beauty and symmetry), sexually-mature (breasts and noticeably wider hips) women for child-bearing from a distance, so visual perception is key to that, and it still strongly affects our behavior today.1