In other words, episodes that went above and beyond in terms of kissing the guest stars' butts and practically hitting the audience over the head with the idea of how awesome and perfect (https://tvtropes.org/pmwiki/pmwiki.php/Main/CharacterShilling) the guest star and their characters may be.

If the guest star is playing themselves, than this could naturally age very poorly. One good example (https://screenrant.com/episodes-simpsons-aged-poorly/) of this is that episode (https://en.wikipedia.org/wiki/Beyond_Blunderdome) of The Simpsons with Mel Gibson (https://simpsons.fandom.com/wiki/Mel_Gibson_(character)). Of course, this was a few years away from when Gibson's public image and life really started to unravel (https://lebeauleblog.com/2012/01/06/what-the-hell-happened-to-mel-gibson/). But here, Mel Gibson's problem is literally, that he's just too likable.

Backdoor pilots (https://tvtropes.org/pmwiki/pmwiki.php/Main/PoorlyDisguisedPilot) (especially for shows that ultimately don't come into (https://www.metv.com/lists/11-forgotten-and-failed-backdoor-pilot-episodes) fruition (https://www.thethings.com/backdoor-pilots-that-never-saw-a-full-series/)) could fall into this. These episodes push the main cast aside to focus on characters that we likely haven't seen or heard about before. And in most cases, we may never see or hear from them again.

I think the John Ritter guest star on Lucille Ball's "Life with Lucy" is a good example. The first half involves nobody knowing who he is- John plays himself. Then once it is proclaimed that he is indeed the famous actor, every character is falling over each other trying to make him happy.

Forgot to mention that it was ludicrous for John to play himself rather than his Jack tripper as his slapstick antics were very much part of the chaos in the hardware store. It's silly to believe that the real John Ritter would be so accident prone and zany.