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: The man who is a pessimist before 48 knows too much; if he is an optimist after it, he knows too little.'\n-Mark Twain
This tweet contains emotions: 
optimism, pessimism, trust