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Awesome Funny Main Trivia VideoGame YMMV
The Main Games (Vanilia CK, CKII)
Any time you, the player, achieve something that seems impossible in the scope and the setting of the two games, such as unifying and establishing the Empire of Britannia early, or surviving in Abyssinia, or bring a fallen Dynasty back into prominence. You can achieve the impossible.
Leading a successful Crusade, and earning the admiration of your vassals and allies. Bonus points if you create the Kingdom of Jerusalem.
Seeing your plotting and political manoeuvring come to fruition as you ascend in power and prestige.
In the same vein, going from being a lord of a paltry 2 counties to owning a Kingdom consisting of 14 instead. Modest in the grand scheme, but still impressive.
Installing your dynasty onto the throne(s) of great kingdoms and empires, bringing prestige to your family name.
Victory through intrigue! Instantly ending an unwinnable claim war by assassinating the claimant. Isolating your enemies by assassinating the spouse who secures a powerful alliance. Tywin Lanister or the Salarians would be proud.
The Expansions (Sword of Islam, Sunset Invasion,The Republic, The Old Gods, Sons of Abraham, Rajas of India)
Reforming a faith doomed in real life and allowing it to flourish in your name. Especially for the Norse, since the character you are reforming the faith with, has fought to seize the Holy Sites of the Nordic Faith and becomes ''the Fylkir of all Norsemen''.
Expanding your Republic into new territories, becoming a regional power and controller of multiple trade hubs under your family's name.
Restoring The Roman Empire ( Legacy of Rome) and the Patriarchs of Alexandria, Antioch, Jerusalem and Rome; not only do you reunite Catholic and Orthodox Christianity, ending the Great Schism of 1054, but you also get the Reconquest Casus Belli for every single Kingdom formerly under the Western Roman Empire, turning Romanion back into the beacon of civilisation.
The Sons of Abraham expansion has a event chain where your child is the Antichrist. Almost everything that happens as a result can qualify.
Essentially the whole of Rajas of India on a meta-level of awesomeness; expanding the world map all the way to India and essentially allowing the following:
Using a proper understanding of the combat system - the mobility of ships, attrition, good commanders, retinue specialization, and terrain - to defeat bigger armies than your own!