Oh yeah, loads of GAS—and that's not including all those I've tried a few hours and concluded not interested. I'm lucky tho, in that beating or completing a game is rarely a goal—sometimes is, mostly not—and that story is low priority, therefore I don't get bored with lack of new stuff. Gimme more glorious gameplay!
♣ Civilization games—apart from a few first runs thru a new Civ, I don't complete at least 90% as the end game is usually less interesting, and my personal goal for that game is usually realized soon after mid game.
♦ Far Cry games—I played FC1 a lot, but only completed once… the second half when the Trigen [monsters] were introduced was very different, became a lot more uninteresting melee combat.
FC3 I completed twice, to get both endings, but replays since stop after all side missions are done and story starts to take precedence over gameplay. FC Primal I can't beat Ull, one of the 2 final bosses, and beating the other boss is boring, so I quit when it's that time.
FC5 & New Dawn I haven't tried to complete. I've learned now to watch some gameplay of endings, on the premise of 'Fool me once…', and they look tedious. I have a feeling FC6 will be the same, the one region I've completed so far was half & half, and the other I just failed is a typical combo of Space Invaders and Asteroids.
♥ Crysis and Crysis Warhead suffer the same fate as Crytek's earlier Far Cry—a major gameplay shift at halfway when the aliens become an adversary. I typically replay each annually, but stop at halfway—I've never completed either.
♠ Total Annihilation & Supreme Commander—Superb games, but I don't think I finished either in any playthru. Their big drawback for me is the emphasis on compiling massive armies, which for me significantly reduces the strategic and tactical variation.