" Doing things we know how to do well is enjoyable, and that’s exactly the opposite of what deliberate practice demands…. Deliberate practice is above all an effort of focus and concentration. That is what makes it “deliberate,” as distinct from the mindless playing of scales or hitting of tennis balls that most people engage in. If "

― Cal Newport , So Good They Can't Ignore You: Why Skills Trump Passion in the Quest for Work You Love