When I was six, my dad (I now know jokingly) told me I was adopted. I believed it for a decade until we had a row about something completely unrelated that climaxed in my screaming "YOU DON'T CARE BECAUSE I'M ADOPTED!" Ugh!
A childhood belief about family

others believed things like this
- When I was younger, my cousin used to try to convince me that I was adopted and I sometimes believed it."Anon
- My brothers to piss me off sometimes told me I was adopted, and that I was the housekeeper's kid.— ricolarno
- My mum told me and my brother that we were adopted and that our real mothers were witches. Thanks mum.Anon
- When very little I completely believed the mascot for Lucky Charms was the Almighty God.— Brendan
- I once believed that the walls and ceilings were completely jam packed with plumbing and wiring.— David
- I believed that wind was caused because the trees moved. I was completely sure my conclusion was correct.— Glenr