23. HILL VALLEY’S PHONE BOOK NEEDS A COPY EDITOR.
The 1955 phone book spells Doc’s name wrong—it should be Emmett, not “Emmet.” At least they get his occupation right!
24. DOC BROWN LIVES IN AN ARTS AND CRAFTS MASTERPIECE.
Doc’s original house at 1640 Riverside Drive (or John F. Kennedy Drive if it’s 1985) is actually a historic landmark in Pasadena, California called the Gamble House. Designed by architects Charles and Henry Greene for James Gamble of Procter and Gamble fame, it’s a prime example of the Arts and Crafts architectural movement made famous in the late 19th century.
25. DOC'S GARAGE IS OF HISTORICAL IMPORTANCE.
A newspaper clipping in the opening scene says Doc’s mansion somehow mysteriously burned down and the surrounding land was sold off, which is why he’s resorted to living in the property’s old garage at 1646 John F. Kennedy Drive in 1985.
Later, Doc tells Marty, “It's taken me almost 30 years and my entire family fortune to realize the [time machine],” so we can infer that Doc, along with the proceeds from selling off the surrounding land, burned down his mansion to collect the insurance money to fund the creation of time machine.
26. DOC KEEPS HIS MENTORS CLOSE.
The same framed photos of Albert Einstein, Isaac Newton, Ben Franklin, and Thomas Edison above Doc Brown’s mantel in 1955 can be seen above his bed in the retrofitted garage bungalow in 1985.
https://www.mentalfloss.com/article/549729/back-to-the-future-things-to-look-for-mistakes