It seems like cats are afraid of the most random things, what are your cats afraid of?

Mine are afraid of:

Bubby - Tin foil sheets, the spray bottle (when he's bad), knocks on the door, men he's never met before with loud voices

Priss - She's not afraid of the vacuum really anymore, she wouldn't come out from under the bed when we got our ceiling fans installed (THAT was quite an ordeal), the Pur water filter (because it's new)

Lucky - the vacuum

I'm sure I'm forgetting some.
None of my cats like being around me with the hairdryer too but I don't think they are AFRAID of it.