This doesn't beat #1 (Used the Last Roll of Toilet Paper) or #2 (Disputed Yahtzee Rules), and it was only an attempted killing, but it does deserve to be on the list.
On September 16, police in Shreveport, Louisiana, said that Richard Brooks Jr. had been arrested and booked on charges of aggravated battery and possession of a concealed weapon after he attacked his friend, James Lawrence. Reportedly, a deputy saw a jeep run a traffic light and then pull into a local medical center. Lawrence emerged with a bloody shirt held to his neck.
Deputy Chris Wray said that the two men and two female friends had just left a nearby business "when the two men began arguing about who would ride in the front seat. During the argument, Lawrence's throat was cut."
There were already two warrants out for Brooks's arrest, making it a particularly bad time to stab a friend over rights to the shotgun seat.