I'm trying to reconstruct a song that I heard on the radio when I was a little kid. It seems to me that there was a male vocal group, and they sang:

First you say you do, and then you don't.
Next you say you will, but then you won't.
tumty tumty tum tee tumty tum
So what am I s'posed to do?

I googled this, and found that strangely enough, the first line is famous enough to be included in a lot of psychology threads, but the song itself seems to have been forgotten.

The song came in handy in my kitchen the other day as a way to end an argument on a humorous note.