Why do most men just look at women but never say anything?

I will try to discreetly look at a woman that I find attractive, but it wouldn’t be appropriate to tell a stranger she looks good as that could come across as threatening. Or if she doesn’t consider herself attractive, it could sound insulting.

I suppose I could make small talk, but in most cases, there’s no reason to, and besides, neither of us wants the interruption. If it’s a situation like waiting in a doctor’s office, the grocery checkout line, or something similar, I do strike up conversations with people. If it’s someone I see often, I will interact if it’s appropriate to the situation.