Why is pee so funny?

Before 2 weeks ago pee did not really play a large role in my life. Yeah it's a necessary bodily function that you have to do a few times a day but it's not really something you give very much thought to since it's an essential part of daily life and it's private. So now I have 2 funny stories involving pee.
On Thursday I had to pick up all 3 kids, Emma and Søren from their daycare and Rasmus from his. I got the older two first and we started to walk home. There came a time in the walk where we had to decide whether or not to cross the street. Søren and I crossed but Emma didn't want to. Søren and I kept walking, figuring that Emma would eventually run to catch up with us. We got about a block away from her and she still wasn't following. Søren and I stop and I call her name and tell her to come. We're standing there waiting when all of the sudden I look at Søren and he's peeing in somebody's hedges. I was already flustered because Emma wasn't listening and I just started cracking up, telling him to be quick, hoping no one would drive by while he was baptizing the bushes. It was a perfect moment where frustration was alleviated by good old-fashioned toilet humor.

On Friday morning Michael and I were getting the kids ready and we were trying to decide whether or not to send Rasmus to daycare with a diaper on. His daycare mom, Tina asked us not to because he had been using the toilet all week. We had him go on his little potty seat and then we took him into the room with his changing table to tell him that we weren't going to put a diaper on him. Upon hearing this news, Rasmus promptly pissed on the floor. I thought it was funny but probably because I didn't have to clean it up.