American Dad! is what happens when a CIA dad with the personality of a human-shaped Fox News notification gets trapped in a house with a hippie daughter, a theater-kid son, a talking fish, a disturbingly complicated alien roommate, and a wife who has somehow remained married to him through all of this.
And then the show gradually realizes Roger can literally be anybody. That is the moment the series' brain chemistry changes forever. Roger disguising himself as increasingly unhinged people, Stan's spectacularly stupid attempts at masculinity, Steve's puberty-induced catastrophes, Klaus being permanently sentenced to the role of “nobody in this household respects you”—there's a lot here that can be genuinely hilarious.
But the series is also a beautiful mess with 399 episodes worth of receipts. The early political premise isn't nearly as important later on, which is arguably good because the show becomes much freer, but it also means American Dad! sometimes feels like it has wandered away from its original identity and forgotten to tell anyone. Some episodes are wildly inventive; others are just characters being assholes to each other until the credits arrive. Roger can be brilliant or exhausting, Stan can go from funny asshole to please get this man away from society immediately, and the surrealism occasionally becomes an excuse rather than a punchline. Still, when the show catches fire, it can be insanely funny. It's less a perfectly constructed sitcom than a laboratory where the writers keep throwing increasingly questionable substances at Roger to see what happens.