I used to think that the Night Safe outside a bank did what the cash machine, or "hole in the wall", does: that you could stick a note in it (presumably with your name and bank details) and get money out. Thus, I was ahead of my time, as I was a small child in the late 1970s/early ‘80s, in the days before "holes in the wall"!
A childhood belief about money

others believed things like this
- I used to believe the Wall Street Crash of 1929 was a literal car crashing into a bank.Anon
- We would drive by UNION BANK here in California and I would say "Onion bank!" My Mom would bust up laughing.— BINGO
- i used to believe that if you were broke that you could go to the bank and get money for free!— Karianne
- I used to believe that as long as there were checks in the checkbook, there was money in the bank.— Michelle
- I thought it was against the law to carry around a lot of money unless you were putting it in the bank.Anon
- I used to believe that a bank was a place where they give out money to peopleAnon