Breasts in Public

So I was on the train today, and I saw the very attractive lady sitting by the window. Very nicely dressed and all and then I noticed her breasts. the dress was so low cut I got a very nice view of cleavage. Slim girl with quite nice boobs. But then I got to thinking, why to women wear such things and expect guys not to look and ogle? I mean …. you wouldn’t hold a million dollars in front someone and expect them not to reach. What would be your take on it? is it better to look away and let her enjoy showing of her breasts or to look and admire as long as you can? or …. look with out directly looking? I’d love a woman’s take on it.