Without being a Mourinho fan, I kinda understand his meltdowns. By his own words he never saw any future on a project where the main goal was not to win titles. If there are no titles to win, the that job is not for him. And when you have such a mindset, it is very easy to get overboard by being extremely demanding with your own players (Robben himself said that Mourinho was the most demanding manager he ever had) and when you start to see different levels of energy and desire, things can only get worse and worse.
The only way I think he can improve, is if he has changed his mindset with his long time away from the training ground. Because at Porto he didn't exactly had the pressure to be a champion the way he did: he was hired at mid-season (because Porto didn't wanted to risk loosing him to their rivals), and those six months were not particularly good, with some embarrassing results like being dominated by Sparta Prague. He was hired for a rebuild and if possible to win something.