Characters in drama are left-brain challenged. That is, at the time of performance the character's (and hence, the actor's) right brain is holding holds sway. Reacting to an unsettling event, it dominates their character-lives. Their creative, emotional, intuitive self, formerly in balance with their left-brain logical self, is overwhelmed by a surge flow of right-brain neurons (in other terms: emotions); and it leads them into their present tragic or comic predicament. They desperately try to shift their behavior, re-organize and redirect that flow of emotions/neurons back into a left brain strengthened balance (all this through the achievement of their character's goal) to achieve a renewed and peaceful logical balance.
Thus a character performance becomes a teeter-totter, initially thrown into chemical/emotional disequilibrium by a prior unbalancing event or events (sometimes the character's whole life!!); and the character's performed story becomes how can the character achieve balance again, to right the teeter-totter, to seek a new equilibrium through the achievement of an importantly desired goal.