Ever get that feeling when you're pushing the vacuum around the lounge that the damn thing isn't actually hoovering anything up?
It could be a blockage, it could be a full bag, or it could be the fact that your vacuum cleaner has developed its own artificial intelligence and has actively decided to wind you up.
One thing it couldn't be, of course, is that the tube to the actual machine has come loose and you've been pushing a plastic stick about the floor for the past 15 minutes, now could it?
Oh, wait... Ah. That'll be it then. At least no-one was recording you doing it on camera, eh?