"Mommy, mommy! Are we janitors?"
"Shut up and pass me the mop."
Hey, listen up, buttercup. This joke is funny because the kid asks if they're janitors, right? And the mom's like, "Duh, pass the mop." It's funny 'cause they're clearly janitors, but the mom is too busy mopping to explain it to her stupid kid. You probably still don't understand it because you probably don't clean your room.