I used to believe that salt and pepper were opposites i.e. that salt made a meal more salty and pepper diminished its saltiness.
A childhood belief about salt

others believed things like this
- i thought salt made food cold, since pepper made it *hot* — cattiva
- I used to think that pepper was only used to mark where you'd put the salt.— BK
- I never used to understand why salt was bad for you, but pepper wasn't.— Lara
- I use to believe that salt would cool food down while pepper would heat your foodAnon
- I believed Dr. Pepper was pepper-flavored medicine and was afraid to drink it.Anon
- when i was a child (of course)i used to believe that the sea is salty because God throws bags of salt into it.— Kafka