I like singing in the shower. Don't always do it because I'm not always in the mood. I whistle in the shower too, but that can be hard with water on your lips.

I think I kind of knew this which means I didn't know it but it makes perfect common sense. A few reasons why it is thought that people enjoy singing in the shower.

Cool little tidbit/article from exploratorium.edu, The museum of Science, Art and Human Perception. Check it out, if you care.

http://www.exploratorium.edu/music/questions/shower.html