i think anything above 65-70 is unacceptable.
people have different preferences. being extremely warm natured (or is it the opposite?), i can't stand lethargic office workers that want it to be 80 degrees all the time. leave that shit at 70 and get a sweater; unless you want me to work naked, with frequent trips to your cubicle to wring out my ball sweat.
working as a mechanic, this can be especially annoying. i was at one dealer that had the parts dept and out equipment room on the same thermostat. you'd think, 'okay, at least you can just get what you need and get out,' but a) mechanics spend hours at the freaking parts counter and b) equipment includes tire machine/balancer, lathes, presses...lots of stuff that has to stay in the room. mix that with rangewalking back and forth between parts/tools and the bay(s) where you work all day...jesus christ i'll end up sweating my balls off on a 25* degree day....then i have to go outside and retrieve a car...fuck!