Blue is my favorite color, and it is between violet and green on the light spectrum.
Well pink is mine, why do you love blue and not other colors?
I just like blue, purple is nice too and that is right between red and blue on the spectrum.
So what's blue associated with?
Blue is associated with the clear daytime and deep blue sea.  There is an effect called Rayleigh scattering.
Does it have anything to do with ones mood?
It does, blue is an emotional state.  Also, blue eyes are cause by the Tyndall scattering effect.
How about royalty?