I used to believe that in the middle of a hot tub there was a big whirlpool that would suck me in and never let me go if I crossed the hot tub. I think I got this idea from my mom telling me once not to swim in the middle of a hot tub.
A childhood belief about bathrooms

others believed things like this
- I used to believe my middle name was and. At age 12, I discovered that it was actually "ann".Anon
- I used to believe that my middle name was Goofy, even though it's actually Margaret.— Lisa
- I used to believe that everyone had the same middle name as me... Elizabeth.
(even my uncles)— K.O. - I used to believe that the red thing in the middle of a Greek olive was the pit.— Liz
- I used to believe my middle name was spelled "Worn" it is "Warren"— Bart
- I used to think the reflectors in the middle of roads were pieces of cheese!Anon