A few for me were the trade notifications.
The Chruch/Schneider for Milledge deal made me want to go postal.
Then when Nick Johnson was traded to the Marlins (then the "Florida" Marlins) for a Minor League Pitcher we have yet to see, who I think has since been traded I was ticked at the team for at least a week. Bad deal for the Last Expo.
Dumping the entire coaching staff except for St. Claire when axing Acta I think messed up any consistancey the team had at the time.