Dear accordion player, I miss the note you got wrong

For three months I crossed the Zocalo at 8.30 every morning and heard the same accordion tune from the same man, always slightly wrong in the same place. I started to time my walk to it. By the end I was humming the wrong note on purpose. Last week I came by and there was only an empty corner. If you moved or found a better spot, that one wrong note is the one I miss most. I would like to hear it again. I would not tell you it was wrong.