I well remember discovering the generator action of a motor when I was young. We had an old Morphy Richards spin dryer for clothes, with the switch operated by closing the lid. The linkage also operated a physical brake pad on the motor pulley to bring the drum to a stop quickly.
I discovered it was more fun to just pull the plug and listen to the motor slow down gradually. Then I discovered that it was slightly less fun to accidentally grab hold of the exposed pins of the now-disconnected plug while the motor was still turning at a fair rate!