In all seriousness, if someone is trying to learn about how to build good maps, they should definitely not just look at maps that they consider good. Much more is learned from bad maps. Level design is far more about what NOT to do than it is about what TO do. At least initially. Learn about what makes a map suck, and don't do that. There's not much point in trying to learn about what makes a map good until you've figured out that first part. Cobbling together a bunch of 'good' ideas will result in a bad map.