Try making peace with an AI at full strength. Now try making peace with them when the AI is very very weak. Note the simlarities in their responses. Also see how they delcare war. Note that sending a full army of deadly soldiers would be a good way of starting a war.
Also, the pope is a bitch. I would rather be excommunicated then comply with his constant "STOP ATACKINZ AND BUILD MOAR TEMPLES BLARGE!" whine. Its simply a 20% hit to public order. I have done great (Up intil the end where Europe hates my guts), and I have been under excommunication for almost the intire game. I also went to join a crusade once. Utter waste of my time. It went like this: The pope had called a crusade. This was back when I was still listening to the bastard and quickly made an army to join up. I sent a experianced general and a full stack of my best units ( A bunch of Miltia Spearmen with leather-something armour and peasent archers. Hey, it was early in the game. And besides, it was a big stack. ), put them on a boat, and had them sail off. However, they place of the crusade was in the Middle East and I was England. .It was a long trip, and the Pilgrims and Crusade Knights I had hired to help also abandoned me ( What a waste of good money! ) . Those units were slowly killed by storms and other bullshit, but most of them survived. However, after 5 something years of travel for my troops and aging general, I found that the city was already about to be attack by future evil rival, The Polish! (Bum Bum BUUUM!) And due to a stupid path finding error that could've been avoided, the Polish began their attack, and I could do nothing about it. Oh, and on the very long way back my "good chums" the French (BumbumBUM!) did me the favor of sinking my fleet, the intire army, and my second best (To my belief) general all in one strike!
Also, on the topic of bullshit general deaths, my first greatest general, Henry (Alias, The Scared, the Mauler, the Mercful, and the Honourable), was on his last conquest before I sent him back to England. He single handedly cripled the French, Milans, Scots, and the Holy Romans. He never fully conquered any of them (As different people did that for him), but he took a damned lot of land for me, he was my single most badass general too (Having Gold level experience and shitload of Hitpoints), he once killed a full army by himself (Though that may have been someone else), and I adored him for his high "Good" rating. He was on his way to conquering the last of the Holy Romans, when he is killed, not of old age (He was in his mid-50's), but an ASSASSIN. Ironic, seeing as I had used them all the time, once killing the pope with them! His nephew Leonard took his place, future conquered all of Italy and more "good" then Henry! He paled in comparison to almost all of western Europe, but he made due. I planed on him seeing his homeland once again too, but guess what came along and ruined his (and everyone elses, including mine.) day! THE BLACK PLAGUE! Almost my intire family was infected, including good ol' Leo, in his conquered castle in Sicily at the time. He surivied for most of it, but when it was about to end, DING DONG! LEONARD HAS DIED OF PLAGUE!
I also notice my sharp decline in how I play the game. At first I was a nice guy, only occupying and releasing all my captured enemy soldiers. But during late game, I became much more agressive. TO give you an example, before I had an always occupy policy. Now I have an exterminatus policy, which states that if a settlement was a bitch enough to capture, I SHALL BURN IT! BURN IT ALLLLLL!!!! It stand among many other questionable "Policies". Ironicly enough, During my good boy period, I had some of the most malevolent rules of my land. Now that I have a bunch of cruel policies, I am starting to get more bevolent rulers.