6. Bob
Bob Newhart is one of the biggest names in sitcom history. The Bob Newhart show is still highly revered, and even Newhart had some success, and even tweaked itself just a bit, even if the premise stayed the same. That cannot be said for Bob, the forgotten Newhart vehicle. The show only ran for two seasons, but that was enough time for some major changes. During the first season, Newhart was a comic book writer who was hired to bring back his old 50s character Mad-Dog, and the show was about him dealing with being back in this changed world of comic books. Then, at the end of the first season, everybody got fired and the comic book was cancelled. So, in the second season, Bob was hired as the president of a greeting card company, and had a whole new set of characters. It didnt take, and Newhart couldnt find himself a third sitcom hit.