Wanders into work and sees guy who was ill last week is back in. I cover for him on a daily check for a client so I ask 'Are you in all week, as I'm off Friday?'
At which point he replies 'I know you are and, according to the holiday calendar, you're off next Monday as well.'
At this point I went 'What?'!
After double checking with the holiday booking sheets it appears that I'd completely forgotten about a days holiday I'd booked.