"Sour note" is a term used to describe something unpleasant or disappointing, and its antonyms include words like "delightful," "pleasurable," "enjoyable," "pleasing," and "satisfactory." Something that leaves a good taste in one's mouth is said to be a "sweet note," which is the opposite of a "sour note." Other antonyms for "sour note" may include "happy ending," "positive outcome," "smooth sailing," and "harmony." These words convey positivity and a sense of satisfaction. It is important to express ourselves clearly, and using antonyms properly can help us convey our thoughts and feelings more effectively.