The best thing to do is to not be foolish in this Saudi-Iranian pissing contest. Sunnis and Shias will figure this out. Eventually. All jihadists should be routed to Syria and Iraq where they will thin their herds.
If I only cared for sunnis and shias, I would hope for them to quiet down. Instead, I will be bringing popcorn.
I have met a few Iraqi men, knew one pretty well. They were so excited for the new beginning that America gave their country. I think about those guys and their families when I read about ISIS.