This is a poem about watching the person you used to be get replaced by the person you became, and being unable to point at the moment it happened. Haseen sitam is the engine of it. Sitam is cruelty, the thing done to you. Haseen is beautiful. Put together they make an oxymoron that film songs had already worn thin by 1959, and here it is doing real work: the ending was lovely, and it was a crime, and the two of those were the same event.
The first passage states the case in two lines. You did not stay you, I did not stay me. Then the meeting: our impatient hearts met in such a way that it seemed we had never been apart. The poem grants the whole happiness in two lines. And in the next breath both of them are lost, two steps into the same road. Nobody else appears in this poem. No rival, no family, no misunderstanding. Just two people walking together and ceasing to be themselves.
The last passage is the one that earns the song its place in the film. Where to go, nobody knows. We have set out, but there is no road. What are we searching for, no idea. The heart is weaving dreams, dam-ba-dam, breath by breath. That is the most honest part of the song. The search is real and its object is unknown, and the dreams keep getting woven anyway. It is not despair. It is walking.
Guru Dutt filmed it on himself, and the film failed, and the song kept its own life. Geeta Dutt's recording is the one everyone means, and Saregama's reissue is the version most people have heard. It is still the first thing anyone reaches for when they talk about Kaagaz Ke Phool, and the credit that survived the film is Kaifi Azmi's.