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: Letting go of anger is key to happiness. Please help me let go of these angry feelings. #happiness #anger
This tweet contains emotions: 
anger, joy, optimism