My mother would whistle one line from a Christmas song any time of the year, over and over and over until I complained. I'd get 5 or 10 minutes of quiet, then she'd start again. When I say "one line", I mean the tune part of "Deck the halls with boughs of holly falalalalalalalala" AND THAT WAS IT. These days I don't seem to have much patience, but I somehow managed to not kill her--not even once!