Singing in the Shower, Writing in the Shower?

A little bird told me...

Okay, somebody on twitter mentioned getting writing inspiration in the shower, and I was like, "NO WAY! ME, TOO!" Apparently, this is not rare. So I thought I'd evaluate this on the blog. 

Why is the shower such a fantastic place to get writing inspiration?

Some ideas:

1. The acoustics are fabulous for singing, and singing probably triggers the creative part of your brain. I have no proof of this, but I'm still going to state it. 
2. Running water provides white noise, which automatically puts you in a relaxed state and blocks out distractions. Suddenly, things that eluded you become crystal clear. (e.g. "Oh, he's a shapeshifter! Now his attitude towards cheese totally makes sense! Why didn't I see it before?")
3. There are no kids, dogs, cats, (or other people, usually). In the absence of loved ones, you can actually focus on your own thoughts, hear yourself think, as it were.
4. You aren't holding still. I think the act of completing a routine task like shampooing or shaving, or the like, stimulates the brain without taxing it. Voila! Perfect conditions for sprouting creative ideas.

So it's a combination of being alone with your thoughts and having distraction-free time to ruminate. 

I just finished the first draft of a novel, and the shower was invaluable in helping me to flesh out characters, creatures, and action sequences for the climax and ending. 

Of course, I prefer a long, salty soak in an over-sized tub, but starving writers cannot be choosers. It would be an interesting study, though, to find out which produces more quality creativity: the shower or the tub?

In the end, it's what you do with the pen or keyboard that truly matters. 

But I'm curious: Do you write in the shower? Where else do ideas flow for you?