The only way to learn chess
Playing is the only way to learn chess. This sounds very obvious, I know, but somehow this realization came quite late to me. I used to think that studying is the best way to master chess, so I read a lot of books, analyzed my own games and generally approached chess as if it was science. Soviet school was very good at preaching that Can't say that it was completely useless, but this kind of "book knowledge" did not always translate well into my own games.
The blitz game below is a nice illustration. It was played in an opening that I play my whole life and in a variation that I both studied and even played in correspondence chess before. I thought that I knew as much as anyone about this variation... And yet when the opening phase ended, I disintegrated in just a few moves
Needless to say, this game (that lasted not more than 7 minutes!) probably taught me more about this position than I learned in literally hours of study.
Gotta play chess more often!