…can cause bands to break up and friends to fall out.
Because for many artists – personal identity is too closely connected to our art.
And so when someone questions our artistic opinion or disagrees with our artistic view it can hurt, because it feels like they are telling us we are a bad person. And hence we can get upset.

But we’re not. Or maybe some of us are (!), but if we are it has nothing to do with the art we produce.
Artistic differences really don’t have to become personal. But they can and will, unless we as artists find some self-worth outside of our art.