What development in Korean culture occurred during the Koryo dynasty

Era of Good Feelings, also called Era of Good Feeling, national mood of the United States from 1815 to 1825, as first described by the Boston Columbian Centinel on July 12, 1817. ... The “era” proved to be a temporary lull in personal and political leadership clashes while new issues were emerging. Now the Era of good feelings can be a bad thing it’s not exactly all good things even though it might sound like it Id describe it as a feeling that can result to a good and bad thing.