i know a girl who thinks its hilarious and acceptable to hit men... she does it because its a laugh, she knows most of them wont retaliate - she's an idiot obviously, and i warned her that one day one of them will kick the crap out of her, girl or not (she thinks because she has kung fu experience that she is 'hard') and i also noted that one day one of their girlfriends may be watching and they will hit you back ... because if you hit my boyfriend i would break your nose.
i was also once 'push/punched' in the face by a girl once, for no other reason than i was talking to her fella - a man i'd known for about 10 years, (i had known her for that long too) - she was mad at him for some other reason, and hit him then just turned and hit me too.
I reacted instantly and hit her back ... then i found she was pregnant - but i was then the big baddie because i'd 'hit a pregnant woman'... which is of course very bad, on the surface, but of course the circumstances were not that straightforward - in my mind, if you are pregnant you should not be risking hitting people in the first place, especially not ones who are out on a night out and been drinking, and if you do, you have to accept that you may get hit back.
but it irritates me that some people think various things about them make it ok to hit other people with immunity, and then become outraged and shocked when they get hit back.