To learn is hard work. It requires discipline. And there is much drudgery. When I hear someone say that learning is fun, I wonder if that person has never learned or if he has just never had fun. There are moments of excitement in learning: these seem usually to come after long periods of hard work, but not after all long periods of hard work. -- Eliot Butler
I would add that some learning is fun, but much of it does involve the hard work, discipline, and drudgery Butler speaks of.