The term "most longfaced" implies a sullen or gloomy expression, but there are many antonyms that convey a more positive and cheerful outlook. These include "bright", "lively", "jovial", "animated", "buoyant", "exuberant", "vibrant", "gleeful", "upbeat", "festive", "merry", and "jubilant". These words all suggest a joyous or enthusiastic demeanor, and can be used in place of "most longfaced" to describe a person who is happy, optimistic, or enthusiastic about life. By using these antonyms, we can shift our language and mindset towards a more positive and uplifting perspective.