Now that I am thinking about it, I believe so. I had built a small room for my sim to sculpt, it wasn't anything fancy. I always put a radio and at least a couple of nice things in there, well, I put one of those wavy lights in there, from the wedding set. My sim went in the room to look at the sculpting table, his mood was about half way, just under the mark. His favorite color is geen and I have pretty much always made their lights the same color as their favorite. Anyway, I changed the light color to green and put nothing else in the room, he went back in and I noticed his happiness bar had gone up, almost to the top and then when I turned the radio on, it hit the top, so, I assume that colors affect their mood somewhat. May not be much, but added to favorite music or anything else and at least it helps some.