Task: Categorize the tweet's emotional expression, classifying it as either 'neutral or no emotion' or as one or more of the specified emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that reflect the tweeter's state of mind.
Tweet: @TweeriaLee A stumbling block to the pessimist is a stepping stone to the optimist.
This tweet contains emotions: 
optimism