What is the meaning of don't know why I didn't come by norah Jones?

In the song "Don't Know Why" by Norah Jones, the lyrics express a feeling of confusion or regret over a missed opportunity or a failure to act. The singer reflects on not understanding why they didn't take a certain action or make a particular choice. The phrase "don't know why I didn't come" could suggest a sense of longing, uncertainty, or self-questioning about a past decision.