I am amazed by how common the use of the term "pee" has become.

To me, this is one of the lowest slang terms. It isn't dirty, it isn't racy, it doesn't sound edgy. It just sounds like an uneducated little kid talking. People should be embarrassed to use such stupid baby talk (and get this straight: even as babies, our family didn't use that word).

Why do people use this word?

If you need to use the restroom, just say so. There is no reason to specify what you are going to do in the restroom. For little kids, you can use terms such as "#1" or "#2" until they are old enough that (a) it doesn't matter (to you, anyway) which function they need to exercise in the bathroom, or (b) they can use less trashy terminology.

Really, no one cares what you are actually going to do in the stall, so announcing your need to "pee" isn't necessary. It is sharing, in fact, too much information.

When talking with your doctor about such body functions, you can use proper terminology. Trust me, in medical school, they use big words like "urine" and "urinate".

"Pee" is to urine as "poop" is to defecate.

Do people really need to talk like babies?

What would you say if during a job interview you needed to take a bathroom break? Would you use the words pee and poop? Come on people, let's try to act like intelligent adults.