Corner Gas/YMMV

Complacent Gaming Syndrome: Lacey becomes annoyed when she creates a new sandwich (the Ruby Club), and it becomes all anybody ever orders.
Epileptic Tree: When minor character Wes stopped appearing, people began to make theories about it. Lampshaded when he appears in the 5th season finale:

Hank: I thought you died or moved to Winnipeg or something...
Wes: Nope, I've always been here. You guys just didn't seem too interested in calling me.

Fridge Brilliance: There is a cold open which ends with Brent saying "At least I don't drive a stupid yellow car." It's subtle enough that you probably didn't notice, but Brent does, in fact, drive a yellow car.
Hilarious in Hindsight: A joke in an early episode has Davis explaining his theory that Battlestar Galactica could have actually happened. Just plausible enough from the original series. But if you flash-forward to the finale of the reimagined series, this is exactly what's said to have happened.
Special Effect Failure: In the Christmas episode, Oscar and Emma's car has been digitally added into the exterior shots of the house.
Squick: Brent once installs a security camera in the titular gas station. At the end of the episode, his parents... play a game in the store while it's closed. The camera catches footage of it. The...leadup is shown to Lacey with Brent and Wanda in the room. He denies any romance behind it after Lacey mentions how she supposes all parents have a hidden love life (his parents spoke of "checking under a hood") and has ripped the camera off the wall.