There are a few reasons why this double-spin off is a total miss: First of all, both Sam (from iCarly) and Cat (from Victorious) were foil characters on their respective shows, with the funny weird stuff to offset the more well-defined, balanced characters. Here we have two comic relief characters and no one to offset them. Look at 'Friends': The ill-advised spin off, 'Joey', was an absolute train wreck, because Joey as a character was not strong enough to occupy an entire show. Sam and Cat are just not strong enough as separates or together in this same way. Both Victorious and iCarly also had strong premises, whereas the premise of Sam & Cat is extremely weak. They're living together and they've started a baby-sitting service. That's pretty much it. There are a few throw-in characters, like a little black market-dealing kid, but none of them add anything to the already weak concept. Nickelodeon was grasping at straws trying to come up with a reason why these two girls would live together and what they would do. My biggest complaint, however, is that when you take Sam away from the iCarly cast and Cat from the Victorious cast, their characters are basically just annoying. Putting them together doesn't help anything. Sam is just a really bad person all the way around, and Cat is borderline mentally retarded. To sum it up, going from iCarly and Victorious, this is a huge step down from both. Not nearly as funny, or interesting, or relatable in any way shape or form.
Review of Sam & Cat
