These are often cited as the reason a band breaks up, but a band in Italy called Soul Cry  took theirs to extreme lengths.

THE singer in an Italian teen gothic metal band and her brother allegedly stabbed the band’s guitarist dozens of times because he did not play well enough.  The 18-year-old singer, Cristina Balzano, and her 16-year-old brother, the band’s bass player, were arrested on charges of premeditated attempted murder.  Police in Genoa, on Italy’s northwestern coast, said the 16-year-old victim remained in  hospital, but his life was not in danger.

In a further show of band harmony, the victim accused both the others of stabbing him, Ms Balzano initially said she was trying to stop the victim from committing suicide and her brother has accused her of being the sole attacker.