At the end of the mass,the priest says something along the lines of "The Mass is ended...let us go in peace" and everyone says "Thanks be to God".When I was a kid,I didn't realise this was actually part of the mass:I thought it was a spontaneous thing that once the priest said the mass was finished and everyone could go home,they were so happy that they said "Thanks be to God".
A childhood belief about church

others believed things like this
- I am Catholic. I used to believe that the Father presenting the Mass was in fact God himself.— Lindsey
- Since we receive bread at Mass, I thought he was called "Jesus Crust" Seemed pretty obvious!Anon
- when i was little i asked what time midnight mass started.
i honestly had no idea.— what time?? - I used to think my priest was a bit foolish for never having noticed that Dog is God written backwards— anticap
- I used to believe that Madonna's Papa don't preach was pop-a-long priest— Mark "lyric master" Rowbowtohme
- I used to think that the priest at church was JESUS.
He had a beard.... it made sense— Joe B