I learned it by watching you!
I learned it by watching you! was a large-scale United States anti-narcotics campaign by Partnership for a Drug-Free America. Launched in July, 1987, the campaign used a televised public service announcement.
The PSA features a father confronting his son (Reid MacLean) in his bedroom after finding a box containing an unspecified controlled substance and drug paraphernalia. After his father angrily asks him how he learned to use drugs, the son shouts, "You, all right?! I learned it by watching you!" As the father recoils by realizing the error of his ways, a narrator then intones, "Parents who use drugs have children who use drugs."
In popular culture
Much like another infamous PSA, This Is Your Brain on Drugs, the campaign is notorious in modern internet culture for its confusing premise and lack of lasting effect and notability, and has been parodied multiple times.
Another parody is in the Kraft Macaroni & Cheese commercial "A Father's Lesson," from 2012 in which the narrator says, "Parents who skim have kids who skim." In the 30 second version, it was extended to "Parents who skim Mac & Cheese have kids who skim Mac & Cheese".
It was parodied in a 2005 episode of Robot Chicken called "Toy Meets Girl" as a sketch called "Watching You" where the son screams at his dad that he learned about crossdressing from watching his father.
It was also parodied in a 2007 Xavier: Renegade Angel episode "Pet Siouxicide." In the episode, Xavier extracts Native American blood from an Indian burial ground and injects it into an oil baron. Later, the oil baron is seen injecting himself with Native American blood. When Xavier asks him where he learned to do that, he replies, "From you alright, I learned from watching you."
It was referenced in a 2011 episode of The Cleveland Show called "Your Show of Shows" where Rallo's remarks of "I learned it by watching you" to Donna and the ensuing announcement regarding karate."
It was referenced in the 2014 "House Call" episode of Archer: Vice on FX.