The best of friends and the worst

I have realized that it is possible for these boys to be both the best of friends and the worst at the same time. They have been playing with each other wonderfully for weeks now. But, when they decide they are done. They are D.O.N.E. and everyone can tell. They have also been sleeping in each other's rooms with each other every night for over a month now. They are awake for an extra hour fighting and then laughing, but I don't stop them. I absolutely LOVE hearing them belly laugh at night. It is pure joy to me.