When we had our last dog, I remember thinking "how much help is he going to be as a guard dog if he's scared of a vacuum cleaner?" but for all you dog owners out there who are thinking the same thing, consider yourself lucky. The alternative is a whole lot worse, let me tell you. When I dig the vacuum out, Indy gets super excited because for him, it's play time! He has the most fun running after the vacuum, chasing it with his tail wagging. He always likes to stand exactly where I need to go next. It drives myself, and whomever else tries to get the task done, absolutely bonkers.
I can't say I haven't considered taking the cord off and sucking him up a couple times just to see if it freaks him out enough to leave me alone. But don't worry, I haven't. Yet.