Why do they check out “regular” women?

What I mean is women just going about their life in regular clothes, even full winter jacket on and everything. I sort of came to terms with scantily clad women because heck, if someone had their but hanging out, it’s hard for me to not look, too. Taking a second, long look is definitely not cool, but I get why the first look is hard to avoid.

But just some lady in line at the store in jeans and a winter jacket? Why? Why spend time checking her out?