The closer you wear your glasses to your eye, however, the more of your field of view they cover:

80°	60°	50°

With my glasses all the way in my field of view is only slightly restricted, while with them further down my nose many more things require angling my head. Lots of people seem to be happy wearing their glasses farther down; what am I missing? Discomfort? Fashion? Not taking the time to adjust them to where they'll stay farther up?