I do as well, but I think my issues are more than just not riding. I ride off road during the winter, so I still get my two wheeled fix.
My dad owns a tree business, so I grew up with winters being slow and not having as much money to play with, plus he was always on edge because of the lack of income. The grass is brown, all the leaves are off of the trees, etc. I'm an outside kind of guy, so when it's cold and dull out, I end up inside more than I'd like to be.