sense
It's G.'s birthday (flatmate/friend) today, and I've just given him a brand new nose and ear hair trimmer (the perfect present to spell out "you are so old hair comes out of your orifices") and a card.
As it's customary, I've written his name on the latter, only to wonder seconds afterwards: why do we do that when we hand the card in personally? In my case, it was only a matter of seconds to walk the few feet from my bedroom to the kitchen, where G. was having tea. Did I do it in the extraordinary possibility that more than one friend was having his birthday today in my kitchen? Or was it careful foreplanning, in case I dropped the card on my way there and then wondered who it was for? I think I just did it so that G. will not be able to re-use the envelope for someone else (unless they share his name). Ha.