Mark Brendanawicz in Parks and Rec. I think he was supposed to be the calm and sensible one in a cast of looney, but good lord he was boring. I guess people didn't necessarily hate him, but he was so bland they just forgot him. He never made any more appearances after leaving, and was never mentioned. Even in an episode where Ann is reminiscing about her past boyfriends, they didn't mention him because he was so unlikeable that the writers forgot about him.