I got into the show in the early 90s when I was in High school,a nd loved it while in University, along with many classmates. SInce the Movie was released it wasn't so much a case of "The show sucks", it was just, there had been so much of it so I got into the habit of just doing other things and not caring.
With a new show every sunday, syndicated episodes more than 4 or 5 times a day during its peak (Sure I didn't HAVE to watch them all, but there'd be little else on worth watching, and often I'd just run into them while flipping, or while waiting for the next show to start since they were often in the "Just before primetime" Slot), like Seinfeld, even the episodes you had enjoyed before you just couldn't bear to watch.
Also, as someone else once pointed out, the show seemed to really focus on Homer every week, to the point where his "zany" hijinks became the focus and the other cast (aside from the occasional focus) just seemed to be background for him.
Yeah not as big a fan of the early seasons so much (Although I maintain, you look at any successful long running show, the early episodes look far different than what the show becomes known for).
All time favorite was episodes were the one with Hank Scorpio, the one with Sideshow Bob's Brother Cecil, although just about any Sideshow Bob episode was gold, Bart's webcomic Angry dad (WIth Stan Lee Cameo..best line ever "I think stan Lee's Mind is no longer in MINT condition" and when Stan is trying to change into the Hulk "Oh please youcouldn't even turn into Bill Bixby"), Krusty stops selling out (Only to sell out to the greatest Simpsons commercial jingle, the CANYONERO), Bart the Boyscout (Junior Camper) and the early one where Bart gets a Big Brother and Homer ends up fighting him.
I do get the "nostalgia", or looking back with rose tinted glasses. Ninja Turtles, Transformers, GI Joe, all cartoons I loved as a kid, and thought were the best, until I watched them as an adult and all I could think was "Was I really THAT stupid that I thought THIS was good?"