[numpad0]

I think it's untreated underage burnout.

The imagined authority and declared lack of execution both allow him to reject expectations from others thereby taking out uncertainties. Absolutely in no offense, the last line of your comment is not an unpredictable response and also emotionally not aggressive, which I suspect is what he is expecting from people around. People in the state of burnout also won't work hard, because the soul is already spent from having previously done so. They don't seem to try to meet or exceed expectations despite looking mostly healthy, though they might think they're capable of or remember themselves to be.

Japanese education for a child in upper middle class during 2000s was horrible. It was essentially a 12 hours a day double work starting 10-12 years old that ends at university entry exam. That creates basis for excessive overtime and workaholism culture that will burn out some graduates within first three years of work if they had not already. Perhaps if they do and declines to be mourned early they'll end up here.