The fender bender Judy causes as she crosses the street to the Bristol Hotel was added on the spur of the moment. When no stunt cars were available, Peter Bogdanovich instructed a crew member to rent two cars and make sure he got collision insurance. Then he staged the wreck before returning the battered cars.
Ryan O'Neal parodies one of his earlier performances. At the end of the movie, Judy Maxwell says, "Love means never having to say you're sorry," (a line from Love Story (1970)), to which O'Neal's character, Howard Bannister, replies, "That's the dumbest thing I ever heard." They added a pause cross cut because the laugh was so loud after Judy's line that Howard's line could not be heard.
As his part is inspired by the stuffy professor played by Cary Grant in Bringing Up Baby (1938), Ryan O'Neal met with Grant. The only advice he received was to wear silk underpants.
The long-haired blond delivery boy whose bike Judy steals is played by Kevin O'Neal, Ryan O'Neal's brother. The woman she sits next to on the plane in the final scene is Patricia O'Neal, their mother.
The pizza restaurant where Judy Maxwell watches pizzas being made was a real pizza restaurant at the time and remains virtually the same to this day. It's located at Bush St. on the corner of Jones.