So true! It always amazes me how much influence sunlight can have on our state of mental wellbeing. Although, I sometimes wonder if it's all due to conditioning. I read an excellent book called "The Art of Learning" by Josh Waitzkin (international chess prodigy and jiu jitsu competitor); he talked about how from when his son was an infant, anytime it was grey/gloomy outside, he would exclaim "what a beautiful day!" in order to try and break the societal conditioning that sun is better. Who knows if it stuck with his kid, but an interesting strategy nonetheless.