Why can't we all just get along?

Today my girls seemed to be at each other all day long. She won't play with me . . . she touched me . . . she said this . . . she's being mean to me . . . it's her turn to do that job . . . I wanted to sit in the special chair . . . . I am trying to figure out how to teach my children to love and serve one another, and to keep from being the referee in every little squabble. It made me wonder how God feels about how His children get along with each other, and how He has managed to watch us all fight with each other over centuries and centuries, in little ways and in big huge ways. It started early in the history of the world, with Cain and Abel. Human beings just don't get along with each other very well. I guess God doesn't referee our fights very often. Most often he lets the battle just run it's course. Maybe He weighs in on the side of the good, if there is one, in some cases when He needs to. So what does this mean for me as a mother with my 6 warring nations battling over borders and commerce, and words? My job is to teach by being an example of love and service (which is not always easy, since I, unlike God, am not perfect, and am subject to the same human temptations and frustrations that my children express) and to pray for the best, I suppose. It's interesting to think about how our microcosm of parenting relates to the whole big picture of humankind. My deep thoughts for this way too late hour.