I was out walking with my then 4 year old daughter. She picked up something off the ground and started to put it in her mouth. I asked her not to do that.
"Because it's been laying outside and is dirty and probably has germs."
At this point, she looked at me with total admiration and asked, "Wow! How do you know all this stuff?"
"Uh," I was thinking quickly, everyone knows this stuff, "Um, it's on the Mommy test. You have to know it, or they don't let you be a Mommy."
We walked along in silence for 2 or 3 minutes, but she was evidently pondering this new information.
"I get it!" she beamed. "Then if you flunk, you have to be the Daddy."