Mood: The mood of this image appears to be melancholic and introspective, with a theme of regret. The title 'Regret' and the somber expressions of the individuals in the images evoke a sense of longing and sorrow.

Environment: The environment or setting of the image is not explicitly clear, but the background of the images suggests a mix of indoor and outdoor settings, possibly a dimly lit room and a blurred outdoor scenery. The overall aesthetic is muted and subdued, adding to the melancholic mood.