I love The Pink Purloiner too, it's one of my favorite Season 4 episodes. Very underrated, and SpongeBob is really funny and likable in the episode in his suspicions over Patrick. If you haven't seen it in a while, and remember not liking it, I suggest re-watching it. :)
Single Cell Anniversary was okay in my opinion, but I haven't seen it in a while, so I need to re-watch it today or tomorrow to see if I really like it. A lot of people have been saying that they like it, so I might like it too. And if I remember, I think SpongeBob was likable in this episode.
Treats! was amazing in my opinion. A really great Season 8 episode, and a really excellent Gary episode overall. I loved SpongeBob's inability to say no to his "little Gare-Bear", and he was pretty likable in this one too. And I liked how he was annoyed by Gary, lol. Overall, this episode is as great as Snail Bites, let's put it as that.
Can't wait to see the rest of your list! :)