This one's a complete anti-thesis to Mall Girl Pearl. The plot is stupid, like it's seriously lazy. Thumbs? Seriously? They didn't even make a joke about the possibilities of all these sea creatures having opposable thumbs. However, I think the execution was great for a plot this lazy. It's obviously mimicking the whole 'hero to zero back to hero' formula used in so many movies (especially sports movie).
But therein lies the problem. It's a movie plot. 11 minutes of cramming everything in would make the entire episode feel rushed, and it does feel rushed.
Apart from that, the climax is actually a pretty good book-end/callback, or whatever, and it's infinitely better than Mall Girl Pearl's climax. Everyone seems so nice in this episode, even Squidward seems really nice to SpongeBob, lending him a helping hand. Patrick's sort of funny in this episode, too.
Though more than that, there's just a certain part of me that's entertained with the idea that every overly dramatic thing in this episode is caused by freaking thumb injuries. And yeah, this episode's pretty freaking dramatic. Best part of the episode is when Sandy comes over to visit a depressed SpongeBob and everything gets dramatic, with Sandy telling SpongeBob to "find something you love, something to live for." The sheer ridiculousness of this out of nowhere 'romantic sub-plot' got me good. It was the loudest I've ever laughed at an episode. The rice barn bit was the tipping point, though.
Tell you what though, if there's ever a show that can make thumb injuries as dramatic as this (and make it funny), it's SpongeBob.
Overall, a dumb plot saved by some good execution. 7/10.