American Dad/Fridge

Fridge Brilliance

 * Roger's sociopathic Jerkass behavior makes sense when you realize his personality is pretty much the standard Kill All Humans alien attitude, but with a comedic twist.
 * In "The Greatest Christmas Story Never Told" Roger uses a tape from the future to invent disco. Upon looking at the tape the dancing shadow on the cover looks like Roger with an afro. Why would it look like that? Roger's company ran the disco empire, so when the tape was made they would have put him on it. He assured the tape's existence.
 * Hayley's hypocrisy of being against feminism when she secretly dresses as a Fifties housewife and bakes pies, entering them in contests under the name "Carlotta Montarrey", can be argued when you remember that Stan had her brainwashed when she was a child, so it's entirely plausible that her alter-ego is the result of what Stan did to get Hayley to conform to his own Fifties-esque values.

Fridge Horror

 * Roger's body produces many items that people use for their own ends (the Golden Turds, the body fluid thing in "Deacon Stan, Jesus Man"). He also can't live without being a bastard to everyone. In theory, he may actually be filled to the brim with doucheyness that causes everyone to be murderers or douches themselves. And the fact he  means he may not have much good in him anymore.
 * Add to that it's In the Blood for him to let out his "bitchiness" (before it takes the form of a poisonous bile that kills his species), in other words his entire race is essentially as big a Comedic Sociopath as himself, willing or not (this is hinted at when his backstory is revealed, he was duped into being a crash test dummy for an aircraft traveling to Earth with the claims he was chosen to evaluate the human race, even placing an apathetic note to ignore the supposed crater and corpse the test would leave). Now imagine it, an entire planet's worth of Rogers! Even worse, imagine more of them venturing onto Earth!
 * With Barry, jokes like how his parents make him sleep in a small room or how he was sorry about killing his cat take a darker meaning.
 * He also rarely (if ever) talks about them in the present tense now...
 * When the guys are beating Steve up for getting hooked on Cougar Boost and selling them fake tickets to buy more of the drink, Barry screams, "Let's kill his parents next! Let's kill them all." Maybe the medication don't completely stunt his murderous urges, then...
 * Remember Barry's gambling episode, "because you don't fuck with a fat kid's candy!", so he was planing this from the start
 * American Dad is more or less Family Guy without all the discontinuity. This brings ALOT of the side jokes into fridge horror territory, as usually in Family Guy these jokes are intended to be one-off, where they had no inherent consequences. They do now.
 * How long did people suffer  until he had his  ?
 * And did Stan give him enough time to grow immune to it?
 * Remember how one of the things Stan made Francine forget via hypnosis was that they had a third child who died thanks to Stan stalling on the vaccinations? In the Spring Break episode, Roger makes mention that Francine has three kids, and gasps when she says she has two. Roger knows, and he's never said a word.
 * Also, the idea of having one of your kids die and then having your memory of them wiped is actually pretty horrifying.
 * It may be even more horrifying if you consider a very good chance that Bailey probably never existed in the first place. They showed Hayley's birth in Africa and she didn't have a twin or sister with her then. Roger isn't entirely reliable himself, being more alcohol than alien, and the only real mention of a third kid at all was the doctor having a magic key to Francine's memories and putting stuff in while he's pissed off. More likely, he just threw that in there to really screw with Stan. What makes that even more horrifying, though, is considering the precedent it sets before a person - someone has magic access to your brain, puts in something absolutely heartbreaking and potentially devastating to a relationship, and even if real life evidence doesn't back it up, it still feels real to you and you can't decide if that horrible thing ever really happened... and you've been seeing that doctor every year for years...
 * That's pretty scary.
 * It should be pointed out that Roger says that she "had" three kids. It could be he's counting Libby, Greg and Terry's baby whom she did give birth to.
 * The implication that if Stan took control of parenting Steve, he'd turn out just like Steverino.
 * Haley is apparently 15-16 if she was conceived in 1996...
 * Let's not forget she slept with older men (Stan's boss, that koala guy, Stan's double, etc.)
 * Wait, doesn't Haley go to college?
 * She's mentioned that she is eighteen several times. I guess it's just a classic case of Writers Cannot Do Math.