Sure, but you don't work for that guy anymore, do you?

Heh, no. And he was a major factor in my resignation. We were all pretty sure he fit the clinical definition of psychopath.

My boss screamed at his phone today. I wondered if he realised he'd just set all the employees on edge and lost maybe 2+ person-hours of work for the rest of the day - traded for the momentary release of an angry outburst.

Similarly, your boss might have been technically correct, but a boss who would rather be right, make a point and potentially knock your morale, than boost your morale for free should really be rethinking his approach, IMO.