Well, the only reason why Iraq and Iran have any issue is because of the US. The US CIA had tried to start a coo in the '40's, we propped up Saddam Hussein in the 80's. He goes to war with Iraq. Then we go in and take him down to doing that, after we had gave him all those weapons.
TL;DR: It's our own damn fault. Iran, Iraq, ISIS all of our fault.