We can't walk around with our eyes closed, y'know. If we turn our backs on you we'll just bump into you a lot. It's safer this way.
At least I try not to drool....
Truth to tell, I sometimes notice where other guys are looking, and think "Geez, don't they know how obvious they are? Sheesh!" But then I catch myself doing the same thing.
Yes, we zone out. It's this wordless, mammalian pleasure that's rather hard to describe... like a cat in a paper bag. I sometimes wonder why women (being mammals as well) don't also experience it, actually. Is it drummed out of you?