Gritty games are probably my biggest pet peeve. If a game was always gritty, that's fine, but forcing a previously non-gritty game to be dark, moody, and bloody, often backfires. I find myself gravitating towards the non-gritty installments of games like Prince of Persia and Tomb Raider, just because they were so un-apologetically fun.
Also the over-emphasis on online features. Some of us play the game for the story or the local co-op.