CKII is one of the few games I've played where I've actually had more fun when everything has started to go wrong. I have lost count of the number of times where I have carefully put together an expansion plan over a couple of generations through specific marriages and alliances, all for it to come tumbling down when a relative (or more often, several of them!) has attempted to take the family power for themselves. I then have to rebuild over potentially another couple of generations to position myself to take that power back.

The fact that the developers are still releasing DLC to add more depth to the game is a credit to them as well. Can't recommend this highly enough.