Regret

Why it sounds this way

Regret is a sad chord progression that moves I – vi – ii – V (C Am Dm G in C). The feeling walks home → longing → wander → tension. Most of these are plain triads, so the colors feel direct and the outline stays clear. That matches a small tip for this mood: minor chords lean on blue. That is why it fits a scene like “letters never sent.” Play it on piano or guitar above, and switch keys if you want it higher or lower.