一颗糖酸到伤
[yī kē táng suān dào shāng]
Literally 'A candy sour enough to hurt', indicating a situation when something initially sweet or beautiful has brought disappointment, which hurts so bad that makes one sad and bitter at the same time. It usually describes heart-breaking or disillusioned experience. Maybe someone felt deeply disappointed or deceived in relationships, studies, careers, etc., just as if the sweet sugar had changed into vinegar.