Quote Originally Posted by Dmitri Lytov
According to my experience, ISTj is probably one of the cruellest types. ISTj, due to his weak Ne and Fi, perceives the world as full of aggression; and, being introverted, he often accumulates his fears up to such extent when these fears manifest in the cruellest form.
I don't know if that's fair regarding most ISTjs but it's definitely the case of the ISTj I had as boss.