"Keep America Beautiful - kill yourself."
It's funny how other memes are presaged in the Rockford Files. In one episode, Rockford waterboarded a guy to get him to confess. Not literally waterboarded using a board and pouring water over him, but by pushing him back into a pool when he knew the guy couldn't swim.
In another episode ("There's One In Every Port"), a character (Steve Landesburg from Barney Miller) who has a skin rash says the doctor's going to put him on steroids if it continues. So steroids have been around in the popular consciousness since the 1970s at least.
In "The Trees, The Bees, and T.T. Flowers", a police negotiator remarks how many use the "suicide by cop" method. He doesn't use those exact words but the meme is present.
It's also interesting seeing the cars in the episodes. Some of the smaller ones, like Civics and Accords, foreshadow the modern SmartCar. You also see Gremlins and Pacers!