"He was never in time for his classes... He wasn't in time for his dinner... Then one day... he wasn't in his time at all."
Back to the Future - Easter Eggs & Hidden Details
Easter Eggs
Twin Pines Mall becomes Lone Pine Mall.
At the beginning of the film, the mall where Doc demonstrates the DeLorean is called "Twin Pines Mall." When Marty travels to 1955, he crashes through one of two pine trees on the Peabody farm, the future site of the mall. When he returns to 1985, the name of the mall has changed to "Lone Pine Mall," reflecting this change to the past.
A reference to Stanley Kubrick's "Dr. Strangelove" can be seen on Doc's amplifier.
In the opening scene, the amplifier that Marty plugs his guitar into is labeled "CRM 114." This is a nod to Stanley Kubrick, who used this designation for equipment in several of his films, including "Dr. Strangelove."
A foreshadowing of the clock tower scene appears in Doc's workshop.
In the opening sequence, among the many clocks in Doc's workshop, there is one that depicts a man hanging from the hands of a clock. This is a direct visual reference to a famous scene from the 1923 silent film "Safety Last!" starring Harold Lloyd, and it foreshadows Doc Brown's own predicament at the climax of the film where he hangs from the Hill Valley clock tower.
A Roger Rabbit doll can be seen in an antique store in the sequel.
In "Back to the Future Part II," when Marty looks in the window of an antique store in 2015, a Roger Rabbit doll is visible. This is an inside joke, as director Robert Zemeckis also directed "Who Framed Roger Rabbit," which also starred Christopher Lloyd.