it seems to be the general consensus that the quality of the Simpsons dropped off around season 10. I still enjoy the newer episodes but most of the truly classic episodes are from the first 10 seasons or so
The jokes are still clever, but they're not as layered, and the show suffers because after 30 shows, they are employing increasingly desperate and absurd plots. Homer has also been reduced to a stereotypical sitcom dad (basically an animated version of the King of Queens), which has been the most significant and most disappointing shift. He himself has always been a dope, but he was written and used very cleverly by the original writers, as when he became head of the power plant's union. Now it's just a lot of "look at how fat and zany Homer is." But a lot of the one-off jokes are still as clever as anything else on TV.
Took me a minute and coming to this comment to get it! Great quizzes otherwise, they are making me feel very smart for knowing the first 10 series word for word.