What P4man points out also smoothly blends into the mirror mirror on the wall. who is the greatest mid-east destabilization country of all.
To some extent we can make a point that its Israel, the USA, the EU, and then Iran in perhaps that order. But because beauty and ugly is in the mind of the beholder, maybe we need some external standard to better measure in what amounts to a era in which European colonialism is on its death bed as a spent world force.
So if we look at the number of wars of aggression Iran has started in say the last 60 years, Iran has started exactly zero. While the USA and the Brits conspired on a 1953 coup that allowed the Shah to overthrow the democratic Iranian government. When 25 years later, the Iranian people gave the Shah the old heave ho, Iran once again regained control of its own destiny, angering the USA and the EU who still want to bring back their sweetheart deals that will never happen again. Then the USA conspired to make Saddam Huessein our man in the mid-east, and soon Iraq attacked Iran for no real reason. At the cost of two generations of its population, Iran just barely beat off the attack, and learned they better arm themselves because no one else would. As for Saddam Huessan, he bore the brunt of US anger, and like Noreiga, learned there is no greater sin than being a tin pot dictator that won't stay bought.
Meanwhile Israel has WMD and used it against its neighbors countless times. Starting wars of aggression against all its neigthbors. Lets see, bombed an Iraqi nuclear reactor, attacking Egypy, Jordan, Syria, Lebanon, and seizing territory it can't retain. And in the past decade Israel has gone on orgies of disproportionate rapes of Lebanon and Gaza, sneak attacked bombed Syria, and now embargoes Gaza and basically the West Bank.
Yep, by that criteria, Israel has to be the most destabilizing country in the mid-east.
Second place has to go to the USA, who started military occupations on the cheap and incompetent in Afghanistan and Iraq that likely will not end well for the USA or for mid-east stability. We can also note another thing, Iran and Saudi Arabia have lived at basic peace with each other for 1200 years even if Iran was always Shia dominated and Saudi Arabia was always majority Sunni. But it wasn't until the USA occupied Sunni politically dominated Iraq that the Iran Saudi tensions began. Because then, as soon as GWB mentioned Democracy, it became a huge Saudi problem because Iraq, in the last 60 years became majority Shia populated. Which then meant, Shia dominated Iraq plus Iran now severed all Saudi land links to the larger Sunni majority Muslim world.
As for the EU, they are now wishing they could go back to a world where the Arab world sold them oil dirt cheap, and thus many of them joined in the US occupation of Iraq. But either way, the EU past colonial sins make them somewhat persona non grata in the mid-east.
As for Iran, they studiously avoid wars of aggression, while firmly saying no to being again dominated by foreign powers. They work with the IAEA in a legal program to develop their own nuclear program to generate electricity.
While Israel and the USA revert to the same little boy who cried wolf tactics used in Iraq. And to some extent P4man may prove correct, Iran is simply waiting for the USA to decline as a world power while the USA does everything to decline through no fault of Iran.