Is the title of a song by Randy Hanzlick, who is (or perhaps was) a real live medical doctor who writes (wrote?) songs as a hobby. This particular song was printed on a 45 in 1980 in a run of about a thousand, but is now available on a larger scale as a track on Dr. Demento's 30th Anniversary Collection, which is where I'm getting my information from.
The interesting thing, and the reason that I bring it up at all, is that I just found that same quote attributed to Tom Waits, who apparently used the line in a TV show in 1977. So it would at second blush appear that this line, like all great lines, originated with Tom Waits.
But wait! There's a comment on this page which would seem to indicate that Dr. Hanzlick came up with the title of his song indepently of Fernwood 2 Night. But then again, according to that source, Dr. Hanzlick "saw it written on a bathroom wall," which is suspiciously similar to a quip Waits made about the origin of the line in the interview linked above. Will we never extricate ourselves from this labyrinth of minutiae?
Perhaps the important point is not who said it, but rather that it was said at all. Perhaps the phrase expresses a truth of such fundamental importance that both men gave voice to it completely independently. Yeah. Dig it.