A good exercise would be to date all of these favorite quotes by season to be able to chart when the show really lost it.
A missing favorite: "Embiggens? Huh, I never heard that word before I came to Springfield." "I wonder why not, its a perfectly cromulent word."
I think the show’s prime was from ‘92 to ‘97, the years after it declined slowly but after the millenium, the show became unwatchable, IMHO.