An unpleasant thought you might get when you are reminded of something you might have to do do later on that is not you really want to do.
In the middle of the meeting John got an unpleasant distraction of when last week at lunch break he had to sit in the very back seat of his employee's cx-9 on the way to the restaurant and wished he would not have to do it again today.
Roger: "Henrietta, I must insist, if we are to propagate the family line, you're just going to have to jolly well buck up, lie back and think of England."
Henrietta: "Oh, Roger, I thought you'd never ask! Let's head upstairs for some bedroom unpleasantness forthwith"