These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Brilliance: In the episode "Say Uncle" we Elise's brother (Uncle) Ned has developed a drinking problem. Early in the episode after she says he's going heavy on the beer, she tells him she wants to talk to him, which is a proposal to find a new job. The way Ned reacts at first means he thinks she's going to nag him about being an alcoholic.
Fridge Logic: If Skippy's adopted, how come his sister looks like him?
Which is funny when you consider that the show's creator originally intended for Alex to be an unlikable Straw Republican. But Michael J. Fox proved to be just too likable for audiences to view him as a heel, and the show's writers eventually decided to give him a more positive portrayal.
Harsher in Hindsight: Watching the Keatons preach to Uncle Ned about his alcoholism is kind of hard to watch after Michael J. Fox and Meredith Baxter admitted they had a drinking problem.
The second season Christmas episode shows a flash forward to thirty years in the future and it's mentioned that the economy isn't doing well. This was made in 1983 and in the 2010s the economy is still hurting.
Hilarious in Hindsight: The episode "Have Gun, Will Unravel" sees Steven and Elyse consider and then debate on purchasing a gun for home defense after a burglar breaks into their home, something both ex-flower children would previously find unthinkable. Nearly a decade later, Micheal Gross would go on to play Gun NutCrazy Survivalist Burt Gummer in Tremors, who then goes on to show a monster what happens when it breaks into the wrong goddamn rec room.
At the beginning of the episode "Heartstrings" Alex is celebrating George Bush's win. He tells Andy that he was born under Reagan, Bush was elected, and that he'd have a Democrat free childhood. Bill Clinton was elected four years later.
Hollywood Homely: A bespectacled Daphne Zuniga as Alex's nerdy love interest Rachel in two episodes from the second season.
Misaimed Fandom: Arguably, Alex P. Keaton. While Michael J. Fox (who played Alex) has always been a liberal, many Republicans have been inspired by the character - and even many liberals have insisted that Republicans should be a little more like Alex. Somewhat justified, though, with the character being a Jerk with a Heart of Gold.
In a Real LifeCrowning Moment of Heartwarming, Fox says many rich Wall Street financiers and hedge fund managers who were inspired by Alex P. Keaton have donated to Fox's Parkinson's foundation because of what his character meant to them.
You can add Daphne Zuniga, Jamie Gertz, Stephen and Daniel Baldwin (but not in the same episodes and not as brothers), Jeff Cohen (Chunk in The Goonies), Maurna Tierney, Kevin Dunn (Sparkplug Witwicky in the live-action Transformers films), Betsy Randle (Mrs. Matthews on Boy Meets World), Earl Boen (Dr. Silberman in the Terminator films), Joseph Gordon-Levitt, and a pre-Married...with Children David Faustino and Christina Applegate.
Funny you should include David Faustino and Christina Applegate, because their on-screen dad, Ed O'Neill, was considered to play the role of Steven Keaton.
Tear Jerker: Alex's breakdown after his friend is killed in a car accident.
The mother of Mallory's friend who committed suicide lashing out at Mallory, calling her by her daughter's name and revealing that she's been unintentionally (or not) using Mallory as a substitute.