Not exactyly, but close; it actually comes from being the Ottomans and removing Blurple from the map post-haste...

Greatest joy in this game comes from:

Conquering the whole world while slowly changing the local cultures and religions to yours. EU4's an insane assimilation simulator and an enjoyable one in that way.

Agreed, destroying the Ottomans is always satisfying.

If you're going to destroy the Ottomans, at least give them Hormuz and Aden for five or so years beforehand. Those provinces specifically gain a unique pair of permanent modifiers which only the Ottomans can trigger, and if you're not Muslim yourself you can even use the Ottomans' religion to upgrade some of the local Islamic Great Projects for long-term Stability boons - it is only owning tier 3 projects, not qualifying for their use, which enables the event.

Originally posted by RCMidas:

If you're going to destroy the Ottomans, at least give them Hormuz and Aden for five or so years beforehand. Those provinces specifically gain a unique pair of permanent modifiers which only the Ottomans can trigger, and if you're not Muslim yourself you can even use the Ottomans' religion to upgrade some of the local Islamic Great Projects for long-term Stability boons - it is only owning tier 3 projects, not qualifying for their use, which enables the event.

More detail please.

A country that owns a province with a tier 3 Great Project can receive an event for -10% Stability Cost that lasts for 10 years. This event triggers very quickly, so usually within a few months of not having the modifier, you can get it again (once per province with a tier 3 Great Project).

This means if you time the integration of a vassal which can benefit from a Great Project but which you can't, you can receive the event instead of them. Let's say you subjugate/release Iraq as a Shia vassal. You carefully time their integration to occur just after their local pair of Islamic Great Projects (one of which requires the owner and province to be Shia) are built to tier 3.

Not being Muslim yourself, you cannot benefit from the actual effects of the Great Projects, but you still qualify for the event giving you a decade of -10% Stability Cost. Depending on how efficiently you are expanding your territory, you want to be integrating vassals about as much as you are conquering - careful upgrading and integrating means you get a regular supply of this modifier, which can easily save hundreds of ADM Mana over the course of a full game.

EDIT: Note that some Great Projects can be moved. If they are moved to a province that does not normally have a Great Project, they can retrigger the event, because it is province-based rather than monument-based. If you were playing as Ireland, for example, you could upgrade Stonehenge to tier 3, let the event trigger in its starting province, then move it to your capital and enable the event to trigger again for that province.

*****

Or if you meant about the province modifiers, with the Domination DLC the Ottomans get two unique events if they or a non-tributary subject of theirs owns Aden (and the Ottomans are still Muslim) or Hormuz for about five years. Aden gets +2 Goods Produced, Hormuz gets +15 Trade Power and +5 Trade Value.

These modifiers remain even when the province changes ownership (unlike most permanent modifiers of this kind), which makes them useful for everyone. And since the Ottomans are both the primary nation of the Turkish culture and Islam can be revived as a religion* even if it's wiped off the map, you'll always be able to manipulate the necessary conditions for generating these two modifiers.

*The Persian mission tree lets you decide between becoming Sunni, Shia, or Zoroastrian (or staying your current religion if you fail to become Zoroastrian); and by allowing Funj to revolt out of Nubian provinces, it will get a recurring event to become Sunni every 20 years or so (if it's Christian with 2 or less Stability). If Christianity has been wiped off the map, that too can reappear by allowing Ethiopia to revolt out of Amhara provinces, and no matter its religion, its mission tree will allow the province of Suakin to become Coptic.

A surprising amount of religions can be revived in this sort of way, actually. As far as I know; only the Pagan religions, Judaism, Ibadi, Anglican, Hussite, Orthodox, Hinduism, and Sikhism cannot be. Hinduism technically gets a "one-time-only" possibility of revival if you allow Khmer to revolt and complete a mission, but since Khmer is not a formable, the game will not let the mission event fire again, and even AI Khmer can sometimes luck out into completing this early.

As Portugal, meticulously routing trade from China and researching tech 14 to unlock Trade Station manufactories. Then building them everywhere because you're super rich and finally quitting before a single one completes because you're bored.

Originally posted by LASci:

As Portugal, meticulously routing trade from China and researching tech 14 to unlock Trade Station manufactories. Then building them everywhere because you're super rich and finally quitting before a single one completes because you're bored.

I like trade games. I prefer Venice, though. I find managing colonies kind of boring.