In the "Like it" column, you can put the governments of Iran, the US, Russia and Europe.
In the "Don't Like it" column, Israel, Saudi Arabia and the anti-Assad opposition in Syria.
If the Iran nuclear deal, finalised in Geneva in the small hours of this morning, sticks, the tectonic plates in the Middle East will have shifted. And whether you welcome that or fear it depends entirely on where you're sitting.
Let's take the "like it" column first. The Geneva negotiators believe they have found a way to reduce tensions over the Iranian nuclear programme in such a way as to enable both sides to claim victory. There is now, they say, much less of a chance that Iran could develop a nuclear bomb, something that Tehran insists it never intended to do anyway.
The Iranians get an immediate partial unfreezing of some of its sanctions-hit assets -- a key element in President Rouhani's election platform -- and the prospect of further unfreezing in the months to come if further talks bear fruit.
Win-win. Everybody happy. Except, of course, the anti-Obama camp in Washington and the anti-Rouhani camp in Tehran.
And all those listed in the "don't like it" column. Israel's prime minister, Benjamin Nethanyahu, doesn't trust the Iranians (never has, never will) to keep their word. He's convinced that whatever it may say in Geneva, Iran still intends to develop the bomb, and to threaten Israel's decades-long pre-eminence as the Middle East's only nuclear-capable state.
Going on past experience, I'd expect Netanyahu to take some kind of unilateral military action (probably against Iranian-backed elements in Gaza, Lebanon or Syria) to demonstrate that Israel is still determined to protect what it regards as its essential security interests. From Tel Aviv, anything that could be seen as good for Iran must be bad for Israel.
The view from Riyadh is oddly similar. The Saudi royals hate the idea of Washington finding a new interlocutor in the region -- and they especially hate the idea that it should be the Shia clerics in Tehran with whom the Americans can now do business.
For decades, the Saudis (together with the Egyptians) have been Washington's go-to people in the Middle East -- and strengthening Iran's position on the world stage is absolutely the last thing they wanted. One of the biggest fears over the Iran nuclear programme has long been that if Tehran really did develop a nuclear weapon, the Saudis would feel compelled to do the same.
Which brings us to poor Syria. Iran has been by far Bashar al-Assad's most important ally since the start of the uprising against him. If Iran is stronger today than it was yesterday, so is Assad. If Washington and Tehran can do business on the nuclear issue, so, perhaps, they can on Syria. And if they do, you can be sure of one thing: Assad will stay in power, at least in the short term.
So as temperatures continue to drop in the Syrian winter, and as tens of thousands more terrified refugees seek shelter and sanctuary wherever they can find it, the fighting will continue. An emboldened Iran may well step up its weapons supplies to Damascus, just as the Saudis and Qataris will be tempted to do the same for their favoured rebel groups.
Russia? I imagine Vladimir Putin is a very happy bunny this weekend. His seizing of the initiative over Syria's chemical weapons arsenal paid handsome dividends and successfully diverted the world's attention away from the Syrian bloodbath. His allies in Damascus and Tehran look more secure; the political dividend for Barack Obama is relatively slight.
Bottom line: if the deal sticks, something huge has changed in the Middle East. The balance of power has shifted. Whether you welcome that, or fear it, will depend on what you think of President Rouhani and how much of a moderate he really is.
It reminds me of the hopes -- and fears -- when Mikhail Gorbachov came to power in Moscow in 1985. That, unexpectedly, led to the end of the Cold War and the break-up of the Soviet empire. Once again, we live in interesting times.