Discussion--Also called a blood feud, we tend to associate a vendetta with its Italian roots. Though we see similar phenomenon in most cultures.
The famous American Hatfield-McCoy feud, or vendetta, reportedly started over a dispute about a stolen hog. In the 1870's the Tug River valley was one of the most isolated in the United States and the element of trust lost over the stolen hog was significant. Five years later some McCoy brothers attacked and killed a Hatfield because he impregnated but did not marry their sister. And thus the vendetta began in earnest.
Recently, we have witnessed many hooligans or so-called soccer fans commit bloody violence in the name of the "game." These activities also begin to look like vendettas, although when the quarrel is about who has the better sports team. Life seems especially sad.
Everyone who's been wronged wants some form of revenge, but self-restraint is necessary to a peaceable society. The courts are often a better venue for irresolvable conflict than bloodshed.