I am far from certain about many, many things:
How computers talk to each other, how germs make you sick, why the base would give me paint that doesn't match my walls, and where every single pair of sunglasses I own is.
One thing I do know for sure is that I live with a four-year old boy. Here's how I can tell:
I hover over my own toilet;
I say things like 'You can't snap your pants with that drumstick in your underwear';
I believe that throwing dirt at the wall is a good idea, because the alternative is a skewer fight;
I am actually pleased when Weston and Shane want to sit still for three seconds to watch TV, even if it is Tom and Jerry; and
All day long, I hear 'Sorry, Shane!' (Sorry I accidentally cut you with scissors. Sorry I hit you in the head with a truck. Sorry I spit at you. Sorry I ripped a toy out of your hands. Sorry you screamed and made Mom come in here. Sorry I had to go to time-out).