Let me write this down, mostly as a note for myself: There are similar themes at work within John Barth's The End Of The Road and Jules Feiffer's Little Murders. Little Murders is probably the better work, funnier and more complex, but The End Of The Road is a book that, at the time I finished it, I was ready to declare the best book I'd ever read. It's not, but it's still something.
Anyway, yes, if you haven't done so already, you should watch Little Murders. It's directed by Alan Arkin, came out in 1971, is based on a play, and stars Elliott Gould. Donald Sutherland shows up. It's a black comedy, one that is a predecessor in many ways to Larry David's stuff, but it has more to say about the human condition and how to live your life. It's my favorite movie of the seventies.