What does it mean to dream about regret?
Regret in a dream often holds a wish that something had gone otherwise, and what you would undo is usually the part worth weighing against waking life.
Four ways to read it
Each reading below comes from a named tradition and a cited source, so you can see where it came from and decide what fits your dream.
Freud
Freud would read regret as feeling tied to an act or wish the conscience has not let rest. He held that guilt and the longing to take something back can surface in sleep when they have been kept down. The dream gives the remorse a place to be felt.
After Freud, The Interpretation of Dreams (Brill trans., 1913), public domain.Jung
Jung would see regret as the self looking back to gather what was left undone or unlived. He treated such feeling as part of reckoning with one's own story rather than only a wound. The wish to undo can mark a value the psyche still holds.
Jungian concept (our summary).Modern
Continuity research ties dream regret to waking choices the mind keeps reviewing, the roads not taken or taken poorly. Some accounts suggest dreaming helps us weigh decisions and learn from them. The feeling is best read against what you wish you had done differently.
Continuity hypothesis (our summary).Mythological
Myth turned on the irreversible turn, Orpheus who looked back, Lot's wife who could not help it. Regret was bound to the moment that could not be retaken. Across cultures such tales held that some doors close behind us and must be lived with.
Rosmerta Publishing editorial synthesis (after Bulfinch; Brewer).