Chances are somebody is going to be upset that the temperature is not quite right for them. The battle lines are usually drawn along gender lines. The men are always too hot and the women are always too cold.
Well, it's pretty simple. We aren't used to it. Down south we rarely see temperatures like this. (which is why you're SOOOOOO cold today) And since we don't see temperatures like this too often, we also don't exactly know how to act in it ... or drive in it.