There's another common mistake I notice a lot, but I don't have a snappy name for it. Maybe "Basing a conclusion on too little information." As an example, I

There's another common mistake I notice a lot, but I don't have a snappy name for it. Maybe "Basing a conclusion on too little information." As an example, I recently read an article (possibly on Hacker News?) in which a guy was working on his free-throw. He tried adding more backspin to his shot and made 4/4. He then tried 400 free throws using his old and new technique and found that in comparison, his old shot was better.