Most productive is the antonym for "most counterproductive." Productivity is a key factor in achieving success, and being productive is the opposite of being counterproductive. Productive means that one is producing something, creating value, and making progress towards their goals. Conversely, when one is counterproductive, they are doing the opposite. They are wasting time, resources, and energy, and their efforts do not lead to anything useful or beneficial. Therefore, by being productive instead of counterproductive, one can achieve their desired outcomes effectively and efficiently.