IT support has to be high on the list, all that crawling around under desks..
Quite a while ago I worked in an office where the desks were laid out in large irregularly shaped blocks which lead to quite long under desk journeys whenever there was a job involving cabling with no-one at the desks really knowing where you were unless they could see you through a gap or you accidentally brushed against them.
One afternoon a guy came back reporting that one of the girls was going commando which lead to quite a lot of extra troubleshooting trips being made during the day
We always had a suspicion that she knew what was going on but we never asked.