[shar3333f]

Childhood issues with emotional abuse/bullying can & do cause emotional systems to become unbalanced though.

It is not a matter of pure free will. If our emotional brain has been trained to scream at us with anxiety at a specific situation or if it is constantly on high alert it becomes tiring to maintain composure and outbursts may provide an outlet.

Now, a person can recognise this issue and visit a therapist to seek help with their emotional issues. But it first requires them to have recognition of the problem. I do not think it's an exceptional case where people are oblivious of their emotional brain causing them to have an irrational reaction to a situation. In fact I think it is quite common.