"Sand Castles in the Sand/Shell Shocked" Vs. "Hide and Then What Happens?/Shellback Shenanigans"
"Sand Castles in the Sand" seems to be a fan favorite and considered one of season 6's best, and while I think it's a little overrated, it's definitely one of the better episodes in the season. There's a lot of cool animation and action here that makes this one of the better episodes of the show from a visual standpoint. I don't think it's amazing, since the first 2-3 minutes are annoying and there are similar episodes like "The Fry Cook Games" or "The Battle of Bikini Bottom" that I find better, but the good stuff is good enough to make this episode good.
"Shell Shocked" is another pretty bland episode. It's pretty repetitive, and while I don't find it annoying, it feels pretty empty since almost everything in the episode revolves around Spongebob breaking shells. I do enjoy Angry Jack and his commercial, and he does help the episode a little bit, but as it stands, it's mediocre. Not bad, but if Angry Jack wasn't there, then it might be.
"Hide and Then What Happens?" combines being super annoying and super boring to make a pretty bad episode. The first few minutes feel like painfully slow filler, and once Patrick hides in his rock (which they show to us, completely getting rid of any tension), Spongebob annoys Squidward, Mrs. Puff, and the audience by chasing Squidward and repeatedly saying "Are you sure?" to Mrs. Puff. Outside of Patrick Notstar, who looks cool but his personality is forgettable, the rest of the episode is slow, dull, annoying, and pointless.
"Shellback Shenanigans" is the third of of three "Plankton disguises himself as somebody in order to get the formula" episodes, and of the three this season, this is easily the best one. Plankton gets some good lines and I was never annoyed or bored with it. Unfortunately, while there isn't anything that bothers me here, outside of some good lines from Plankton, it's mostly forgettable and this plot didn't need to happen three times this season. If this plot wasn't overused or if it was a bit better, I might give it a good, but as it stands, it's on the higher side of okay.
I'm giving this one to season 6 since "Sand Castles in the Sand" is good and "Shell Shocked", while mediocre, isn't bad and has an enjoyable character in it. "Shellback Shenanigans" is okay, though it has an overused plot and it's forgettable, and "Hide and Then What Happens?" is pretty weak.
Season 6: 12
Season 7: 9