It's not true that American women are automatically worse than their foreign counterparts; I've dated plenty of non-American women who were screaming cunts.
That being said, I discriminate against American women, because they so often display characteristics, including, but not limited to, the following:
1) Loud, rude and crass without being any fun;
2) Ignorant, boring and uncultured with no ideas, opinions or curiosity;
3) Two-faced, lying, manipulative, controlling (duh);
4) Snobby and arrogant while lacking in both self-esteem and compassion for others;
5) They pitch their voices in shrill nasal tones that sound like nails on a chalk-board. This gets worse as they get older and is compounded by the god-awful accents some of them have;
6) They get fat;
7) They age badly. Once they get hitched, when they hit 28 or the 2nd kid whichever comes first, they hit the Haagen-Daz, get a lesbian haircut, and wear sweat pants, chunky sweaters and a pair of canvas shoes for the rest of their fat-ass life;
8) It doesn't matter how crazy she was in her youth, at age 28 or the 2nd kid she starts acting like her shit comes out in plastic bags and she's some kind of saintly figure engaged in a holy war against fun wherever it may be found. That's why I always find a 19 yr chick with a bunch of tattoos so fucking funny;
9) They tend to have no sense of humor, they don't know something is funny unless there is a laughtrack and it involves the misfortune of others, and then they laugh like a hyena being disembowelled and show all their fillings. Because of this lack their mouths become thin-lipped and eventually pursed into a expression of permanent disapproval, that's why so many middle aged american women have a face like a pitbull licking shit off an electric fence;
10) Crap in the sack; hate to admit they enjoy sex because it would interfere in establishing a transactional dynamic in the relationship and reduce their bargaining power.
That's all that comes to mind right now. But there's plenty more I didn't get to.