system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do people feel comfortable at different temperatures?

For example, I feel most comfortable with the thermostat set to around 80 degrees.  I have a friend that will literally start sweating when he comes over if I don't change it.  He sets his to 69, which I find unbearably cold.

We're both about the same size and build (5'10 ~165lbs) and both have lived in the same city (Orlando) for 30+ years.
gpt
There are a few different things at work here - different people have different levels of metabolism even if their physical sizes are similar. Also, there's the psychological aspect - the ambient temperature at which an individual *feels* comfortable, called the "thermal comfort". There are a variety of other factors as well, such as, clothing, recent activity levels, etc..