Currently doing a rewatch of
Foster's Home for Imaginary Friends and decided to rank the episodes on a tier list as I go. So here's how it currently looks after finishing Season 1 today.

A tier is for the best episodes, B tier are for episodes that are also still good and C is for the OK episodes and the last ones I'd willingly rewatch (but not really go out of my way for). Episodes in D tier downward are the ones not worth watching because they're boring or bad, F is for the episodes that are worse and Z is for the ones so terrible that putting them in F would be an insult!
I actually didn't watch
Adoptcalypse Now, honestly haven't since at least 2005 I think. However, this is based on memory and I remember not really liking this episode back then, largely for the ending which is the first instance I can think of of the mean-spirited tone that becomes more frequent later going too far. In fact, basically any episode that'll go in the C tier downward will be based on memory as even back these episodes were new there some of them always sucked.
I also haven't watched
Where There's a Wilt, There's a Way or
Everyone Knows It's Bendy, nor will I and these rankings too are based on memory. I actually did rewatch the former back in 2018 and it ended up being one of a few that I rewatched during that time that ended up being worse than before, even if it's biggest crime is just being boring.
As for
Everyone Knows It's Bendy... Well, what the hell can I say about this one that nobody else hasn't already said because everyone who has seen it knows how much of a piece of shit it is? Though the fact that in my rankings it's only in F tier and not Z tier should be telling of my scathing opinions of some of the later episodes with the first episode in that tier coming as early as Season 3! At least Bendy's shitshow is only 11 minutes of crap, something I can't say for something like say...
The Big Cheese (or it's even worse POV Sequel
The Little Peas).