In all seriousness though, I understand your question as I wondered the same. In the end this is what I did.
I painted the inside of the coop the same colour as the outside, off white, because that's what I had on hand and the off-white was the same colour as the trim on our house which kept the HOA happy. It is also light and bright and airy which is good for a small coop like mine.
Now I did change the colour of the inside of the nest boxes. After much reading I learned that chickens like to lay in dark, private corners (which is why some people hang nest curtains) but they don't like to stay there and hang out in the dark once the deed is done. You don't want them hanging out in the nest boxes because then they poop in them and make a mess. You want them in, lay your egg, then get out again.
A friend had a left over sample pot of dark green/black paint they had tried on their front door, so I used that on the inside of the nest boxes. The girls have only ever laid in their nests, never found an egg anywhere else, so I think they are happy laying in there, but they have never slept (ie. pooped) in their nest boxes and don't hang out there which is good for keeping things clean. Now, is it the colour paint that made the difference or perhaps I just have very smart chickens??? It is hard to know
So, since you are looking for ideas my suggestion would be to paint the inside of the coop something light and bright, whatever you like, but paint the inside of the nest boxes something dark. Has worked for me (but again, maybe I just have incredibly brilliant chickens who understand the requirements of their jobs)
