This evening I took someone up to the microfilm machines, he said he was looking at something sneakily, outside of work time (but presumably work-related). When we got up there, there was already a man on one of our machines. By the time I'd got the keys out and discovered the years my customer wanted weren't in the drawer,  they were sheepishly shaking hands - working sneakily after hours on the same thing for the same place, by the looks of things. Hilarious... I made my excuses and left them to it.