it happens in movies because it happens in real life too. when in crisis, often there is sense of loss of control or autonomy. for most, something that can provide an outlet for such a frustration is one’s appearance. and, while men do too, women broadly tend to have the more intimate relationship with their hair. so: haircut (or hair dye, or both).
yes! i wanted to mention this, that hair can be a sensory overload problem too so cutting hair can just be a way to optimize sensory performance in a state of stress as well. but i forgot so thanks for the reminder!