Comment by H8crilA

One key feature of learning is that it must involve some form of failure - at least in the sciences that HN is typically involved in. It is impossible to fail at watching a video, but it is possible to fail at deriving a formula yourself on a piece of paper, or at writing a program that is supposed to achieve some goal. The failure and subsequent recovery is exactly where knowledge is gained. This is perhaps why writing code is so much fun, the failure-recovery loop is very short.