What does cloudy weather do to my work.

I am just about to get out the sun lamp. This is terrible. I hate cloudy days and we are having a lot of them here in southeastern Wisconsin. How does it I effect my artwork ? Well, I have taken picture on a vacation when it was cloudy and have tried to go back and take the same pictures when the sun is out. Everything looks so flat without the sun to give it shape with shadow and highlights. How do you feel about cloudy days? Thanks Walt