Here is something I have heard often: 99% of church splits are not over theology, but over personality.
There was a time in my life when this gave me some comfort. Now I think it is just a thing people say to feel better about themselves.
It is as if personality is some kind of blank check for acting like an idiot. Too often, personality is an excuse for not changing. "Hey, this is just the way I am." It's as if personalilty is not a spiritual or weighty issue. Well, we can't just wiggle off the hook that easily, as if we couldn't help it since it was a personality issue.
I don't see Jesus giving us any wiggle room for disunity based upon personality differences. Check out the apostle's personality profiles and you'll see that we can't just play the personality card and allow our guilty consciences to be soothed.
Jesus picked, I think intentionally, a politically diverse group in order to prove that unity is based upon something other than sameness (uniformity).