I have absolutely no qualms whatsoever about peeing in the shower. At the beginning of the shower obviously, lol. And the water is draining the whole time so it isn't like I'm standing in a pool of my own piss.
I also brush my teeth in the shower. I get amused when I admit to people that I do both of those activities in the shower every morning. They are often taken aback that I would dare brush my teeth in the same place I pee. It isn't like I piss on my toothbrush to get it wet! My pee comes nowhere close to the toothbrush or toothpaste or even my mouth, lol. It really isn't gross, I promise.
I do not ever pee in the swimming pool even though I know plenty of others are doing it. I just don't like peeing in my bathing suit. But I will definitely piss in the river or lake if I'm just wearing my grungy "river clothes," or if I'm wearing no bottoms at all.