In 1980 I went on a business trip to Tallahassee (Florida state capital) and we had a bit of a session in a bloke's hotel room. It was a hot day, September and a heatwave across the southern states so somebody turned the aircon up to max. As well as being hot, it was very humid. The result was that it was literally snowing in the room. I wouldn't have believed it if I hadn't seen it myself.
I used to work in an office where the girl who sat under the aircon would wear a winter coat most days in summer
Exactly. She won't have it though. It's normally somewhere around 26 by the time I notice that it's stifling and go turn it down.
Depends. If you are constantly going out and coming in then it needs to be cooler in summer to allow you to cool down from being outside. Although our AC at work is so chilled (or at least it is in the area I sit) that I can sit in a 50 degree car after work and thaw out without any issues.