You learn to write by writing. If you want to learn computer programming, you write computer programs. You learned how to drive by sitting behind the wheel and stepping on the gas. Flying, piano, bicycling:, whatever it is, you learn by doing. Just try learning to juggle without actually tossing the balls into the air. At some point you have to put down the book, jump in with both feet, and (to borrow a marketing phrase) just do it. The instructor is there to show you how it’s done and (in the case of driving or flying) to prevent you from causing damage when you make a mistake.
I have little patience with coworkers who ask me for a book that will “teach me how to write,” or “teach me Delphi.” It’s obvious that they’re expecting to learn by reading rather than by doing the work. This is similar to students who view learning as primarily a passive activity: go to class and somebody will teach. As if the instructor can somehow force knowledge and ability into their heads.
When somebody asks me if I can teach them something, I say “No, but I’ll help you learn.” A book or instructor is simply a learning facilitator. Learning is up to the individual seeking the knowledge, not the person who holds the knowledge. Some people are undoubtedly better at teaching (imparting knowledge) than others, and students who are fortunate enough to have such instructors generally have an easier time learning. Ultimately, though, the responsibility is on the student. If you have a “bad” teacher, then you just have to work a little harder. Nobody said it would be easy. Or fair.
People who want to learn, learn. People who expect to be taught generally fail.