As someone who grew up with AC, I was one time in Brazil and got stuck in a place without AC. Needless to say the first few nights was hell. I just couldn't follow asleep. However after few days, my body just adjust to the local temperature, and really enjoyed it. In fact, going into mall with AC just feels too cold for me then. Of course there is a limit to what our body can endure, but there is something to be said about exposing and adapting our body to the natural elements instead of just adjusting the environment to make what is comfortable to our body.
I live in Phoenix. Very well adjusted to the temperature here. You sweat more. It was 75 yesterday, walked outside, started to shiver. Weird.
There's certainly a level of acclimation but if it were truly as enjoyable people wouldn't bother with cooling/heating buildings except in the most hostile environments.
I live in a place with very little need for heating and air conditioning. If I don't do anything, indoor temperatures vary between 17°C and 27°C around the year. I've noticed that I prefer 24–25°C during the day in the summer and 21–22°C in the winter, and a bit less when I'm sleeping.
When I travel around the US, most places are too cold for my taste. Conference rooms are the worst, as I can't adjust the temperature myself and I often spend hours in them without much physical activity. I guess many Americans don't acclimatize to warmer temperatures, because their summers are uncomfortably hot.
And when I return from long hikes high up in the mountains, even that 17°C feels too hot for sleeping for a few days.