Which of the following is a criterion for an effective mental game?

An effective mental game should incorporate enjoyment as a criterion, as this element fosters engagement and motivation. When individuals find an activity fun, they are more likely to invest time and effort into it, leading to better outcomes. Enjoyment can enhance concentration and performance, as players are more likely to stay committed to practices and strategies that they perceive as enjoyable.

Lengthy duration might not necessarily translate to effectiveness; it's the quality and engagement level that matter more than how long someone practices. Complexity could create unnecessary barriers for individuals trying to master mental strategies. Lastly, focusing exclusively on the individual can overlook the importance of social interactions and team dynamics, which are also crucial in mental resilience and performance in many contexts. Therefore, integrating fun is essential for sustaining interest and optimizing the mental game.