About 10 years ago, the Building Museum in DC had an exhibit on air conditioning in America. I guess it had never dawned on me, but far from being a luxury, without air conditioning we would not have developed our manufacturing base. Between workers getting too hot to function and chemicals and processes that need a certain temperature, there is a lot that depends on having air conditioning.
I felt like a total nerd for going to the exhibit, but it was very interesting.
Without AC the South would not have developed much.