In Goblet of Fire, during the opening feast, only Hagrid and Dumbledore clap for Moody when he is announced as the new Defense Against Dark Arts teacher.
It was usual for new staff members to be greeted with applause, but none of the staff or students clapped except for Dumbledore and Hagrid.... Everyone else seemed too transfixed by Moody's bizarre appearance to do more than stare at him.
Goblet of Fire, chapter 12
How come even the more experienced teachers like McGonagall and Flitwick didn't clap for Moody? Surely they knew of his legendary reputation? And surely McGonagall was too dignified to stare at a new teacher, regardless of his appearance, knowing that it may be impolite? A possible explanation is that they were taken by surprise, but even then, not clapping is odd for them. Plus, isn't it likely that Dumbledore informed them about the new appointment? Could someone please give me an in-universe explanation for this?