@Somchai200, it's getting colder and nobody will be wearing skimpy clothes now, so I'm afraid you'll have to wait till summer to see for yourself.
I've never been to the US, so I can't compare. What I've noticed based on what I saw on TV was that it seems that American women are more likely to wear blouses, T-shirts or dresses with pretty big cleavages. Even at work which would be usually a "no no" in Poland. But that's pretty much all I can say, I guess.
wear these super short buttcheek shorts in any public or social settings without hesitation
Well, that's defenitely not happening where I live in Poland (the Holy Cross region).