Yes, well said Alphaelin. Curiosity is one thing that keeps me reading. If there was nothing left to our imaination and everything was developed and explained to the fullest, leaving no loose ends, then boredom would be soon to sink in. I find that everytime I read any of Tolkien's works (especially LotR) I always learn something new and find myself pondering different questions. I always want to know more, but never do I want to know all. And besides, like you said
When you can do that it makes the world so much personal and likeable to your own appeal. It's up to your mind to develop what you think is beyond. And that way, you'll always love it. Because your mind makes up what you want, not someone elses idea, but yours. And great thing about Tolkien's works is that you can form your own personal image about anything he left up to you to decide. It's unique in its own from and differs from anybody elses. Tolkien's works are kind of a blend between what he made and what he allows you to make yourself. It just makes it so realistic (its own history contributees to that a lot too, as Orual said), enjoyable, and personal.