Oh, knobster. My late husband loved to sing in the shower. Loudly. He often sounded like a room full of wounded animals, but the exercise made him very happy (and we didn't have close neighbors). I never minded the noise, since it was making him happy.
He died in my arms (heart attack) 32 years ago. I wish I could hear him singing in the shower. It is music to my ears even to remember.
If it makes you happy, sing.
Well I'm glad I could bring a smile to your face at the memory of him at least!