I'm not surprised by Tevez at all, he's always been a prick and something like this was to expect sooner or later this season. At the same time, I am appalled with Mancini's reaction and the way he dealt with Dzeko in public, especially given his proven favouritism of Balotelli.
I was admittedly wrong about Mancini before, I now don't think he'll ever make a good manager at this level. He certainly has a lot of vision, he is a fantastic strategist, but his tactical and man-management skills are nearly non-existent. He would make an excellent club chairman/director, but this is not the right role for him. I hope he realises that himself and moves on, though I doubt that will happen.