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: .@POTUS Obama describes his temperament as 'steady &amp; on the buoyant side.'
This tweet contains emotions: 
joy, optimism