My favorite color is blue! There are so many beautiful things that are blue.
I love blue too. Its one of the three primary colors.
Oh really? What are the other two?
Red and Green. Blue, on the spectrum of light, lies between violet and green.
That is very interesting, what is your favorite?
 I like Blue. There is an optical effect called Rayleigh scattering that makes the sky and ocean appear blue.
That is incredible. I learned about that in a college Weather and Climate class. Fascinating stuff.
I find it fascinating that Blue has pretty much always been an important color in ancient times for art and decoration.