I sing in the shower sometimes :D
So do I. I sound better when I sing in the shower.
I like to think I do :) Bathroom singing is a widespread phenomenon
Oh really? And why is that?
Mostly for the reason you described earlier. Many people sing in the bathroom because the surfaces usually create an aurally pleasing environment
Yes and I assume the sound vibrates off the walls nicely.
Bathroom singing
Bathroom singing, also known as singing in the bathroom, singing in the bath, or singing in the shower, is a widespread phenomenon. 
Many people sing in the bathroom because the hard wall surfaces, often tiles or wooden panels, and lack of soft furnishings, create an aurally pleasing acoustic environment. The multiple reflections from walls enrich the sound of one's voice. Small dimensions and hard surfaces of a typical bathroom produce various kinds of standing waves, reverberation and echoes, giving the voice "fullness
that I really like." "Launchpad" similarly writes, "where most bands these days look for that new, original sound to enhance the digital revolution, 'The Lumineers' do superbly in taking it back to simplicity." In another interview, Fraites explains, "I just think people are enamored of going into a room and watching people play their own instruments and sing, rather than using Auto-Tune and a lot of digital equipment to get their sound across. There is so much digital-ness all