When Life is Unfair

If you find that the daily injustices of life make you more irate that most others, it could be that you have an overdeveloped Insular Cortex.

The insula responds to internal body signals, such as pain, heart rate and temperature, but new research has hinted at role for the walnut-sized structure in detecting social norms and fairness. When you have deviations in fairness the insula revs into action, Montague says. – New Scientist

That explains a lot for me.

On the contrary, lack of response to signals of mistrust may indicate a poorly functioning insula and borderline personality disorder.