It's a love hate relationship:

I swear that my kids must be the craziest creatures on earth. When they are home together they love to hate each other. They can't get along for 5 minutes without tearing into each other about something. And the knit picking is a never ending source of enjoyment for them that brings them hours of pleasure. Now let one of them go stay at their Grandmother's for a few days and they miss that sibling like crazy. I guess absence really does make the heart grow fonder, only problem is it only lasts until they are back together. It only takes 5 minutes of them being back in the same house together and the cycle starts all over again.