I heard this 10-15 years ago:
If everyone in the whole world had the same skin color, hair color and eye color, if we were all the same religion, if we all had the same favorite sports teams, drank the same beer, drove the same car, and spoke the same language, if we all hung our toilet paper the same way, listened to the same music, had the same hat size, and used the same toothpaste, mankind would… still divide into at least two groups and find a reason to kill each other.