4. Dr. Marvin Monroe
20th Century Fox TelevisionYou might need to struggle a little to remember Dr. Marvin Monroe because he was killed off early on in the show. Actually, in a plot twist that nobody cared about, he was brought back briefly in the 15th season, simply stating that he had just been very sick, but hasnt appeared since then. As it turns out, he might have been suffering from the dreaded Herman Disease. Initially, he played the role of the medical professional on the show even though he was a psychotherapist, but he was overshadowed later on by better characters such as Dr. Hibbert and Dr. Nick. Now the show had a competent and an incompetent doctor so there was no need for another one. And then there was that shrieking voiceEven Matt Groening confessed on DVD commentary that he found the voice annoying.