How do you feel about Dimitris behaviour?
Actually, very professional and responsive. He heads a superb team of professional software developers responsible for creating and maintaining an exceptionally complex simulation.
Having been a programmer [your comment] I have to assume you have created applications beyond “Hello World” so you should have some appreciation for what is involved. Similarly, based on your overall commentary I must assume you are unsatisfied because everything you ever developed was bug free and worked flawlessly from its inception.
D. may suffer from having a very high threshold for what can best be described as “suffering fools poorly” and you have managed to exceed it.