Task: Classify the mental state of the tweeter based on the tweet, determining if it is 'neutral or no emotion' or characterized by any of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust).
Tweet: Keep #smiling because life is a beautiful thing and there's so much to #smile about. #MarilynMonroe #KeepSmiling
This tweet contains emotions: 
joy, love, optimism