As well as the old exhaust pushing the car thing, I used to believe that front wheel drive meant the front wheels turned, rear wheel drive the rear wheels would turn and four wheel drive meant all four wheels would turn. Valuable years of my life were wasted, that I shall never get back, trying to figure out how this worked.
A childhood belief about cars

others believed things like this
- Because of cartoons, I thought that to drive you'd just turn the steering wheel back and forth constantly. — Mitsuki
- I once thought that there were little mice under the wheel on Wheel of Fortune making the wheel move— Kara
- For some reason I thought any 4X4 vehicle would pull a wheelie when switched into 2 wheel drive.— Richard Davies
- I used to believe that when people talked about 4x4 trucks, I thought it meant all the wheels turned.
— tracy - i used to believe that my brain worked like the inside of a clock. How the wheels cranked and turned.— Becky
- I used to believe that there were lots of hamsters in the wheels of the car, and that's what made it go.— Jade