The varying level of Norepinephrine
A lower than average level of norepinephrine is associated with a lack of the cognitive ability, it also causes fatigue and a loss of alertness. In contrast a high level of it can be associated with panic or the fight and flight response. The reaction of that overdose is similar to adrenaline. It results in increased strength and the feeling that we have to act immediately to the situation.
In this defensive state, however, the more primitive interferes with rational thinking which has a major impact on our working memory resulting in narrow mindedness. In other words, the individual is losing its ability to make an objective conclusion or decision. On a neural level, the brain reacts as if we were threatened, even if this threat is harmless such as the already mentioned deviating opinion of someone else. During that state we perhaps avoid a fact which we may otherwise find helpful. For that reason, I guess, stressed people might say, “don’t talk to me”, “leave me alone” or “piss off”; because all they want is to escape the situation. Or if the person doesn’t want to flight but rather wants to fight, he or she might call you names in order to fight and to protect their own ego. Anyways, it is helpful to understand that chemical, because it makes us aware of our own responses and this awareness helps to avoid irrational behavior.