Fired? Don't delete your company's Exchange database
 

When Akimbo Systems fired him in April 2003, IT manager Steven Barnes struck back at the company by deleting its Microsoft Exchange database and crashing the server. Barnes was able to attack the system because Akimbo hadn't changed its login/password information since terminating him. Now Barnes heads off to jail while Akimbo hopefully learned a thing or two regarding proper IT security.

http://arstechnica.com/news.ars/post...-database.html