Ego depletion
Ego depletion is the idea that self-control or willpower draws upon conscious mental resources that can be taxed to exhaustion when in constant use with no reprieve (with the word "ego" used in the psychoanalytic sense rather than the colloquial sense). The theory proposes that when the energy for mental activity is low, self-control is typically impaired, which would be considered a state of ego depletion.