My favorite Good Reason to Kill remains "Used the Last Roll of Toilet Paper," but this one seemed like an immediate contender. Also seems hard to improve on the lead sentence:
"A night of Yahtzee ended with a fatal stabbing Saturday."
The brief report did not specify exactly what the argument was about, although most likely they were playing under the original 1956 game rules with the well-known discrepancy as to whether bonus Yahtzees may be used as "jokers" in the upper section of the score card, something that resulted in more Yahtzee-related killings than almost any other rule before it was finally corrected.
I also found this other good Yahtzee-related fact on Wikipedia:
"Kelly Clarkson carries Travel Yahtzee in her purse. "
Good to know.
Anyway, it is possible that the fight was over a woman -- the report notes in passing that the alleged killer, Mark Kelvin Allen, had been playing Yahtzee with the victim's girlfriend when the argument started. That sounded suspicious, but the report also says that the argument started between the two players during the Yahtzee game, and that the woman then left and went into another room where her boyfriend was. Allen kicked that door off its hinges and the two men then fought. Based on those facts, this does sound like a killing that started over a Yahtzee dispute with the victim having become involved in defense of his girlfriend. And that puts it right up there on the list of good reasons to kill.
Link: TBO.com (Tampa Tribune)