Throw It In: It's a Robert Altman film, so there's lots of this. Elliott Gould ad-libbed many of Marlowe's quips. The shot of the two amorously-engaged dogs on the street of the Mexican village obviously wasn't planned but was memorable enough to stay in the film.
What Could Have Been: Altman originally wanted Dan Blocker (TV's Hoss Cartwright) whom he originally directed in early episodes of Bonanza to play Wade. Tragically Blocker died from a post-surgery complication at the age of 44. The film is dedicated to him.
During filming of M*A*S*H, Elliot Gould and Donald Sutherland approached Fox executives about removing Robert Altman from the project, but decided not to go through with it. Gould admitted to Altman that he and Sutherland almost had him removed from the filming, but Donald Sutherland never told Altman about it. Subsequently, Altman never made another movie with Donald Sutherland.