Productivity refers to the efficiency of converting inputs into useful outputs. To be productive, one should manage their time in small blocks, learn to say no, find the right environment, be alone to focus, use the right tools, delegate simple tasks, manage their energy, and plan proactively rather than reacting to events as they occur. The benefits of being proactive include eliminating problems, more efficient task execution, activating initiatives, over planning, and ability to predict outcomes, while reactivity leads to zero efficiency, no initiatives, lack of planning, and inability to predict.