How do you feel when men say things like that to you?
I get the feeling I'm supposed to blush girlishly, giggle, and twirl a little, at the very least.
What I actually do is guffaw, and say "Fuck off." 
Followed by a lecture, if I like them. 
Apparently this is breaking some rule, and I should be flattered - and "have to understand" that they just can't help objectifying looking at my breasts being unable to manage not thinking about sex for a bloody minute finding women attractive.
I'm 34. I'm not a girl. And "pretty" is just fucking offensive, to my mind.
Anyway, I am just venting here, I shall trot back off to educate the drinkers of Ireland, one wanker at a time.