In my case I had been boxed all night, and decided that rather than throwing a sickie, I would bosh the last of the base and head into work......
Couldn't concentrate on anything for more than 9 seconds, and kept running into the bogs for a wank, before remembering that I shouldn't really be having amphetamine wanks in the work toilet, returning to my desk, then 9 seconds later deciding I needed a wank...........etc.
It was a long and unproductive day.