shabu addict wears always sunglasses as the sun rays are glaring to them.
All day every day is too much... Wearing them during the day is understandable. Wearing them indoors during the day is understandable most of the time (as long as you don't mean like, at your home or a party. Then it's douchey). I usually forget my regular glasses in the car 99% of the time so I wear my sunglasses (prescription) to go shopping or whatever.
I think it makes the person wearing them look foolish. Unless they're blind of course!