"Five Easy Pieces" refers to a book of piano lessons for beginners.
The moment at the end of the diner scene where Bobby sweeps all the glasses off the table after arguing with the waitress was inspired by Jack Nicholson doing this himself once at a coffee shop called Poopies up on the Strip, when the manageress took his coffee away despite him only having just arrived, because the group of fellow actors he'd joined had been there for hours and were being told to leave.
The traffic jam on the freeway was shot on a new and unopened section of Interstate 5 near Bakersfield, California.
When Dupea goes to quit his oil-rigging job, the loud whirring of machines can be heard in the background. This identical sound effect was used by George Lucas for the trash compacter scene in Star Wars: Episode IV - A New Hope (1977).