I admit, of all the games I've started, I've only finished one!!! (domination victory, Persians). After a point I get bored or some patch induced problem arises, or I notice a critical stupid oversight in my mod (like I forgot to assign a unit cost for republic, so everyone is going republic and building infinately gigantic armies - and its into the industrial age. Aaarrrghh! @#*&^&$$!) Also, I love playing w/ the full compliment of civs, and stupidly overlooked in the editor the ability to allow more on smaller than gigantic maps, so games would take for freakin ever. Also I would start 16 diferent games, switching back and forth until one really grabbed my interest, or I got bored w/ the one I was on. Now I'm trying again, using smaller maps w/ full compliment of civs. A bit vicious early, lots of "rampaging blah blahs" eliminating "fledgeling blah blahs", but fun. A real example of social darwinism if ever there was one. Moves faster too. Got one now as Romans where after millenia of near constant warfare (much as a republic, I might add), I've finally managed to wrap up my entire continent, the biggest, and eliminate (absorb!!!) 6 entire civs. Now quietly building/developping in order to complete the task one day. HAIL CEASAR!
At least I have a great grasp of early/mid strategy, and now that I can handle it, the late game is still kind of fresh.