When i was in Year 3 of School (Age of 7-8) I used to hear the phrase 'off by heart' A lot. I now know it means learning it yourself so you can remember it instantly, but then I genuinely believed that 'By heart' was a TV show that told you everything you needed to know. It really is funny when I think about it now...
A childhood belief about tv shows

others believed things like this
- The song called heart of glass mixed me up as a kid. I heard "Heart and ass". — oops
- When I was in elementary school, I believed my heart moved across my chest throughout the day.— Allison
- I used to think that when people had heart attacks someone came and stabbed their heartAnon
- I used to think that if you eat pig heart, you could grow another heart and be twice as healthier. Anon
- When I was five or six, I was worried that I'd lost my heart because I didn't hear it beating.Anon
- I used to believe that the heart at the beginning of the I Love Lucy Show was made of real chocolate.— Krissa