Apparently, kids don't watch Tom and Jerry anymore. There have been enough smacked faces on my farm that watching this is now a prerequisite for touching my gardening tools.
and if you want something a bit more modern
Seriously - this is a real thing. don't leave tools smack side up!
I hesitate to admit this, but I did that exact thing with a rake once. It was leaning against a planting mound, which tilted the tines enough for me to step on them easily. The rake was in plants deep enough to hide it well. I had just enough time to turn my head before the handle of the rake slammed into it hard enough to make my ears ring. A wholly unpleasant experience, but one that taught me the lesson of not leaving tools lying around like that in a single event.
My dad was a master mason, and often used a tool he called a comealong. He called that move "the comealong trick." "Did the comealong trick? Think you'll pay more attention next time?" No matter what he told apprentices, I think I'm the only apprentice he ever had that didn't brain themselves on a job. (I had done it in the yard enough times to know better!)