Ugly maps, worthless UI, tedious movements, constrained city development, unfathomable diplomacy, slow pace, silly wars, inglorious conquests, boring peacetime, unrewarding victories.
The dynamic in Civ5 is simply broken. Most of the time I boringly push 'Next Turn', waiting for something to happen. Even wars get dull after some time, partly due to the tedious movements, partly to the silly AI placement of troops. No achievement, not even conquest, gives me any sense of satisfaction. Nothing like the excitement felt almost every turn in Civ4. No "one more turn" syndrome.