Most people think Mario knocks those coins out of the blocks with his head. But Mario's no fool. If you look closely at the animation Mario always puts his hand up so he doesn't smash his head on the blocks when he jumps.
Because you can't go giving yourself concussion when you have to run and jump for hours and still have staying power when you finally get to the princess.
Just in case you were wondering, the pipes are not a metaphor.
Have a play.