There is a spectrum of people along the scale of Flower to Mushroom.
Flowers are people who thrive in sunlight. They feel sleepy when its overcast. They throw open their curtains and windows during the day. They are rejuvenated in the warmth and light of the sun.
Mushrooms are people who avoid the sun. They turn lights off, draw curtains. They feel more comfortable on days that are overcast and grey. The light of the sun drains them like in the opening scene of Rango.
I am a Mushroom (most of the time). I used to live in the desert, where the sun blazed down on you always, blinding. Even with sunglasses on you had to squint. I hate the sun. Days that are overcast I feel like I can actually see. The lowered contrast makes things much easier to process. I leave the lights off in my office when my office-mate doesn’t come to work. (Though a night owl, he is a Flower, because he needs the light on in order to stay awake during work). But I also sit next to a window, which I keep open most of the time so I’m not a full Mushroom I guess. 😉