Ensemble Darkhorse: Kelly is actually well liked due to her being emotionally supporting to Benjy and an all around nice girl in contrast to the smug Ronald and the bitchy Betty.
Epileptic Trees: For fans who may like the Thing show in itself but not as an adaption of the character, the joke has been made that this "Benjy Grimm" suffered a mental breakdown from the experiment (that was actually an accident that gave him his thing form) and as a result Kelly (and when applicable others) are simply humoring his thinking he is Marvel Comics the Thing.
Love It or Hate It: Depending on your view of the character, it was actually nice to see Ben "free" of being stuck in Thing form, and actually choosing to transform back to help his friends. For whatever it's worth, the show helped popularize both Aunt Petunia and his catchphrase of being "the lovable blue-eyed Thing, Idol of millions"; he was only short a phrase of being The Rock before there ever was a Rock.
It also becomes easier to be on the hate side as a comics fan but much easier to be on the love side when ignoring it's comic adaptation status.
Squick: Benjy has a crush on the high-school aged Betty Harkness, but he's actually an adult stuck in a teenage body, leading to some (thankfully) never-explored implications.