The best way to learn a subject or material you're really interested in is to gain a basic understanding of it on your own, and then try to explain it to someon

The best way to learn a subject or material you're really interested in is to gain a basic understanding of it on your own, and then try to explain it to someone else who asks a lot of questions. Those questions will reveal holes in your own understanding that you'd have difficultly finding entirely on your own. Taking a formal structured course with graded assignments (or demanding workouts etc.), under the supervision of a paid teacher is mostly useful for when you're lacking in self-discipline (which most of us are to some degree, so it is a good idea particularly to develop necessary skills in areas you aren't all that excited about).