He manages the team with a fear factor that wears off after a couple of seasons. He trashes his own players, always criticize them publicly and shows no compassion for players with a dip in form. Look at Guardiola or Klopp, they are always cheerful, supportive and friendly. Who would you rather play for?
I've seen Mourinho stand up for his crappy players before. I've also seen him shit on his teams. I actually think the players usually don't mind him (except when Chelsea players decided to fuck him over 2 years ago).
The problem is he expects too much from himself while staying totally unproductive. He's too stubborn to change things, but wants different results. This often puts extra wear and tear on his teams. He doesn't build a foundation to add to (like Guardiola does). He just goes in, starts yelling at his players, tells them they're better than everybody else and they should beat the entire world by 4-5 goals (I've actually heard him say this!)
He's a lazy coach when it comes to actual work. He's a hard worker when it comes to public relations and controversy.