Ego Depletion

Temporary reduction in the capacity or willingness to engage in action(controlling the environment, controlling self, making choices, initiating action) caused by prior exercise of choice.

Self-control or willpower draws upon a limited pool of mental resources that can be used up.

Research affected by the Replication Crisis. Not sure if this concept can be believed anymore. A better way of thinking might be willpower as a muscle - it can be strengthened by training.