I'll say first, Annie Laurie, that things don't seem to add up here to me. But then confusion is not new to me.
I took your remark about not being mean teenagers to mean that you were adults. It you
are teens, I guess I'd be inclined to chalk some of your "friend's" behavior up to immaturity.
But if the manager turned on the air conditioning after you left, then your complaint about the heat was well-founded. If you had been inappropriate in your conduct at the restaurant when complaining about the heat, I'm surprised the "friend" would agree to go back to the restaurant with you. Does she love embarrassment?
I don't know you & I wasn't there, but there had to be more to the story as you suggested.
How good a "friend" was this? And do you have a tdoc to rehash this with? Are you on meds under a pdoc?