Martin O'Neill says Portsmouth and Chelsea acted too hastily in axing Tony Adams and Luiz Felipe Scolari respectively.
The Aston Villa manager said: "You get to a stage where nothing surprises you any more but it is disappointing.
"I didn't get to know Scolari too well but he has been a brilliant manager.
"He won the World Cup with Brazil and I was really surprised at what happened.
"In terms of Tony Adams, the first thing he is asked to do is sell players.
"And then you are expected to improve the team even though you've sold those players - and it is difficult.
"Again, in terms of the time given, I thought it wasn't enough."