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: @TweeriaLee A stumbling block to the pessimist is a stepping stone to the optimist.
This tweet contains emotions: 
optimism