Not As Easy As It Looks
When I was younger, I used to think Squidward is so bad and thought the jokes referencing his playing were funny. But when I started playing clarinet, I realized it is not that easy and Squidward actually plays surprisingly well in some of the episodes.FROM CLARINET-NOW.COM
You are absolutely right. Clarinet is not easy.
Also, when you learn any instrument, seeing/hearing someone (or a cartoon character) with experience then becomes suddenly very impressive. You are at that time realizing how respectful the art of playing that instrument is. That is probably the number one job of music education.
So, before you started clarinet, the Squidward jokes were funny. After you started learning the clarinet, you thought, “wow, he is not too bad, he is better than me right now.” Eventually, with regular practice and improvement on your clarinet, your ears will change again and you’ll think those jokes are funny again and wonder why Mr. Squidward has not improved at the rate he seems to love claiming the clarinet.
You are also right that he does indeed play well in some episodes. We all have ups and downs when it comes to practicing. The best results come from regular, steady, everyday practice. Good luck practicing! And have fun playing music.