This is a fun little episode that further establishes the dynamic between SpongeBob and Sandy. I quite enjoy the friendly rivalry SpongeBob and Sandy have throughout the series, I think it's really fun. And this is coming from a DragonBall fan so I'm basically an expert in animated rivalries (this is a joke).
I love the beginning of this episode, SpongeBob and Sandy's back and forth is really entertaining to watch, and it's fun to see them in different environments. The volcano sauce part is equal parts random, weird, and hilarious, which is perfect for a classically SpongeBob joke.
This is the first episode where Mr. Krabs is a real jerkwad ("Help Wanted" I suppose could count, but he didn't really know SpongeBob yet so I don't count it), but it isn't taken too far I don't think, given that he listens to Sandy when she pleads with him. Speaking of that scene, it's hard not to feel bad for our little yellow sponge when he gets fired, but man oh man is his reaction both emotional and hilarious. SpongeBob SquarePants is a show that thrives on making sure we as an audience never feel too sad about anything in the show (I feel like "Have You Seen This Snail?" is the only exception here, and even that episode doesn't dwell on the sad for very long), rather focusing on making us laugh, even in sad moments. This time is no exception, so SpongeBob's exaggerated reaction is mostly played for laughs.
The following segment of SpongeBob and Sandy trying not to do karate like they're going through withdrawals is brilliant and a great use of humor that appeals to both children and adults. Children get that SpongeBob and Sandy like to do karate and are having a hard time staying away from it, but teenagers and up get the whole addict vibe from the scene as well. That's another thing this show does well, but I won't dwell on it here.
Sandy and SpongeBob finally getting their release in doing karate again is also great, it's just entertaining to see them going crazy with it, and then when Mr. Krabs suddenly shows up, that's a great moment as well. The ending of the episode is also very fun, I love that SpongeBob and Sandy get to use their hobby in a way that helps everyone (though why do I get the feeling Sandy doesn't end up getting paid...knowing Mr. Krabs that is). Squidward's "I hate all of you" is a good note to end the episode on too. All in all, just a very solid episode with great examples of what makes this show great.
Episode Tier: Amazing
Episode Score: 9/10