When I was small I wondered what force drove cars along.. I decided that it must be something like a jet plane or a hovercraft, so (obviously) the exhaust pipe was the driving force, with the exhaust "smoke" pushing the car along. Eventually, I realised that this wasn't the case because all the cars with one exhaust would only be able to round in circles..
I had used my awesome powers of deduction and prodigous knowledge of "science" to work it out - I seem to remember being absurdly proud of myself!
A childhood belief about cars

others believed things like this
- Some sport cars have a double exhaust. I wondered why. Why would people want to pollute twice as much?— F*ck the environment?
- I used to think that cars were powered by a jet of air which came out of the exhaust.— BadDeal
- I used to believe that cars were propelled by their exhaust like some kind of rocket.Anon
- I used to believe that car exhaust pipes were what propelled cars, instead of the engines.— Thomas Johnston
- I thought that people were like cars because cars have exhaust pipes, and people fart.— Matt
- I used to believe clouds were formed by jets and their exhaust. — Olivia