Reading is pleasure of the mind, which means that it is a little like sport:

Reading is a pleasure of the mind, which means that it is a little like sport: your eagerness and knowledge and quickness make you a good reader. Reading is fun, not because the writer is telling you something, but because it makes your mind work. Your own imagination works along with the author’s or even goes beyond his. Your experience, compared with his, brings you to the same or different conclusions, and your ideas develop as you understand his. As a result of reading, you will become better, wiser, kinder or more gentle.