There's no denying that if a TV show wants to be successful it's necessary for it to have the proper development with its characters. So there will be many differences from the character in the first season to the same character five seasons later. Most of the time these changes are handled in a great manner and turn an already awesome character into someone even better. However not everything is like that on TV, a character that used to be funny or even relatable at times can become one of the worst parts of the show. Whether it's because of lazy screenwriting or because of some ridiculous fad that's going on at the moment some characters can become really annoying, such is the case of...
5. Seymour Skinner
During the first seasons of The Simpsons he was definitely one of the best characters the show had. Not only was he one of the few with a very solid backstory and a very solid performance by its voice actor, but he was also one of those really likeable and relatable characters which made the stories of the series not only much more entertaining to see, but also more meaningful. Flash forward to season 8 when the character became pretty much a punching bag for every character on the series. Sure he had some good development once in a while however his entire character was destroyed the second the writers felt it would be funnier to destroy the only relationship on the series that had chemistry and turn one of the members involved into a very cheap and repetitive joke. It wasn't funny then and I'm sure it isn't funny now.