There's this movie called Finding Nemo, and at one point, a girl is tapping on a fish tank and it is too loud for the fish, and one of them shouts, "Find a happy place!".
I didn't realize he was talking to himself and meant a happy place in his imagination.
I thought that he was talking to the girl and telling her to go find someplace that would make her happy and therefore stop bothering him.
A childhood belief about films

others believed things like this
- Someone told me People and fish went to the same place.I thought they meant humans get flushed— MrK
- I used to believe that if you used the kids' shampoos that said 'no tears' it would make you happy.— Emmy
- I thought the holiday was called "Merrychristmas" so I would tell people "happy merrychristmas"Anon
- I once knew a girl who used to believe that the sun was actaully a really bright gold fish very high up.— meow
- I thought that there was a law that all movies had to have a happy ending— Quatsch
- I thought my parents had written "Don't Worry, Be Happy".Anon