Why did Dave Duncan hang up on Tony La Russa?
Dave Duncan has been Tony La Russa's pitching coach since 1983, so they probably have a pretty strong working relationship.
Still, your boss is your boss and it's usually not a good idea to hang up on that guy when he calls you about a crucial business decision -- like who to start in Game 7 of the World Series.
But Duncan just felt that strongly about Chris Carpenter, and we doubt TLR is filing any complains with HR over his phone manners.