Producing banal tat that, while popular and pays well, is repetitive and tedious. As pointed out - Gears of War part 1... Gears of War part n. You can't explore anything new or take a chance on something cool because it "might not sell x squillion copies". Same crap over and over and over Ad infinitum.
Its got to be pretty exciting to be at Obsidian, inXile or Uber Entertainment at the moment - producing something exciting and different with more depth than a kiddies paddling pool.