yeah, a good chunk of the US is incredibly over-ac'ed. I especially hate hotel conference rooms. They're set for men in suits, but in summer, I like to wear summer clothes - shocking!
We don't have AC here in Ithaca, and other than a few miserable nights here and there, it's really ok. If you're really desperate, go swim under a waterfall or hang out in the library. But in defence of some -- I grew up in southwest WI where it's incredibly humid and just doesn't really cool off at night. When it's above 85, it's fairly unbearable, just because of the humidity. Having lived in France for a year and travelled around a good bit, I never experienced anything like that in Europe - or at least, it never lasted longer than a day or two.
Yes, people survived before the advent of AC, but they were hot, sticky and miserable.