While I remember Robin Williams using this in the late '70's (maybe 1978) as part of a monologue, the saying had been around since my high school years, and I graduated class of '72. My friend and I remarked at the time of viewing William's monologue that it was 'funny, but not original', as we had both heard it many times before; it was a fairly common remark among our contemporaries, a 'truism', if you will.
This precedes Annie Hall (1977), too. Of course, due to the subject matter and immense disposable incomes of Mr. Williams and Mr. Allen, I can understand why attributing this quote correctly might be close to impossible.
