For me it was Lisa Goes Gaga. It was focused entirely on Lady Gaga who played herself and was awkwardly inserted, I don't mind the occasional brief celebrity appearance or when they lend their voice to other characters (ex. Meryl Streep playing Jessica Lovejoy in Bart's Girlfriend) but they started to feel so forced. I tried watching the occasional episode afterwards but people like JJ Abrams would show up in Do PizzaBots Dream of Electric Guitars? and I'd lose interest.
I have started watching the show again but I am curious who else has lost interest due to an episode or trend especially those who have been watching the show since its beginning.
I actually haven't been a fan for a long time,just bumped into the thread browsing all. At some point a formula for the shows became apparent to me, and I realized for the majority of the episodes, there's a standard series of event-misunderstanding/misdirect-main event/conflict-resolution. Once I saw it, I couldn't help noticing the first 10 minutes of every episode didn't matter and I lost interest.