Women in a state of undress tend to think about their "wobbly bits" as Bridget Jones called them. This probably includes one or more of the "trouble area trifecta" spots: stomach, thighs or butt.
Men, on the other hand, skip the wobbles and let their gazes go almost immediately to their favorite parts, whether a woman's clothed or naked. Truth Merchants' "Ask A Guy" contributor tells us if a man's into the booty, he'll probably start checking out a woman at her feet and work his way up. If the chest's more his thing, he might look you in the eyes before focusing on the breasts.
Whether he's a toe-to-head or head-to-toe kind of guy, what's certain is that he's taking mental snapshots to revisit at a later date. As "Preston Swagger" writes:
"The mental picture we take of you naked is stored in the long term memory bank and can be called upon for daydreams for up to years afterward. In fact, the only thing stored in this area of our brain is mental pictures of you naked and mental pictures of us while doing the hibbity-dibbity. There’s no room in this area of the brain for anything else like your birthday or favorite food or favorite flower. Sorry…the system just wasn’t wired that way. You should direct questions about this to the manufacturer."
In this way, men are visual optimists: they naturally skip over the less-than-perfect parts to see nothing but the best.