A lot of practice that's not directed properly is useless, especially for complex mental skills. For example, I learned Java's stream syntax to the point where

A lot of practice that's not directed properly is useless, especially for complex mental skills. For example, I learned Java's stream syntax to the point where I wrote an article that thousands of people read. Do I remember a single thing? No, because I don't use Java every day. I just remember that it sucked compared to LINQ because every collection type had a different method to turn it into a stream. That's it. From weeks of study, practice, and an article. Mostly a complete waste - if it didn't build into my rep, it would be a complete waste.