Why do men make it so obvious when they stare at a woman's body?

It is part of their genes since more than 60 thousand years and it is not likely to change in the next 60,000 years because the porn industry makes a fantastic job at telling them that breasts, among other female assets, are those they are subconsciously attracted to.

Breasts are just like those electric miniature trains. Both of them are made primarily for children but daddies are the ones playing with them...