Rational fears are boring to talk about (spiders, heights, etc) because everyone has those.
So, my irrational fear for a long time was pool equipment. Yep, the tubes, vacuums, are appliances that you put in a pool to clean them scared the shit out of me when I was younger. I'm a lifeguard now, so I have to work with them, but I'm still a little skittish when I'm in the water with them...they seem like these big squids that are gonna suck me in if I get too close. Amiright?