The Grandness of Paradox Grand Strategy titles is not a misnomer. Shame the grandeur tends to also come with a small helping of bugginess. Crusader Kings 1 is perhaps the poster child for that. The title was initially developed by an outside studio, with a similar style to Europa Universalis but in the Middle Ages with a focus on families instead of nation states. Unfortunately, the outside studio kind of screwed some things up. Even with all the fixes eventually given to the title, there are still random quirks that don't work like they should.
Still the grandeur honestly makes up for many of the blemishes. It is a pleasure to lead a family of small time counts to the head of the known world. Unfortunately, once you know the mechanics, you really have to hold yourself in line to not use them all. It's extremely easy to min max your way to a thorougly boring second half of the game. Don't give in to temptation, and you're treated to stories that can be great fun to remember and share, like the count who went mad, killed everyone, then just sort of sat there with no heirs til you inheirited from the people who were grateful to not have to put up with him or his heirs. Stories that grow out of the gameplay are really the draw from this title.
Also try looking up the Dynastic Glory program. It lets you parse your save game, and compare your family tree to those of other great families. It opens a whole new way to make a mark on the world, spreading your seed far and wide to have your namesake, if not yourself directly, as the top of all the houses of Europe.
Overall, Crusader Kings represents a really interesting game style that should be experienced at least once. You may want to go for a less buggy or more accessible model though. Try Europa Universalis 3, for example. 7.4/10