Jacob learned the reason behind the saying, "puts his pants on ONE leg at a time".

Jake: Daddy can I jump into my underwear.
Dad (holding underwear out for Jake to step into): I wouldn't do that. You will land on your butt.
Jake: OK
Jake (after he attempts a jump into his underwear and lands on his butt on the tile): That hurt.

Jacob likes to learn the hard way. I am glad I didn't get that trait.