He liked to make fun of emerging CS, it was his thing, and he did it pretty well. He wasn't "miserable ass", he was a man of different culture. "Positive attitude" as you used it is a late americanism FWIW. In many parts of the world we often bring our criticisms in similar caustic manner, and we enjoy it while being resilient and optimistic.
It doesn't mean that he was always right, of course.
It doesn't mean that he was always right, of course.