I really liked both episodes.
I really liked the element of mystery in "Earworm." I wouldn't have liked the episode as much if it was just a series of different shennanigans in an attempt to drive the earworm out.
"The Abrasive Side" was nice as well. From the previews, it looked as if the episode was going to be about a "mean fungus" that grew on SpongeBob, but to my surprise it turned out that SpongeBob elected to have it attatched to him in order to become more assertive.
Two very good episodes, in my opinion.