The antonyms for the phrase "most cast down" would be words that convey positivity, hope, and enthusiasm. Some of the antonyms for the phrase are optimistic, cheerful, hopeful, buoyant, confident, encouraged, contented, and exhilarated. These are words that describe a person who is not downhearted, but rather is looking forward to the future with a positive attitude. Positive thinking empowers individuals to overcome difficult situations and helps to find solutions that are beneficial for everyone. Therefore, when faced with challenging times, it is important to stay positive and focus on the brighter side of things.