Task: Identify the primary emotion conveyed in the tweet and assign it to either 'neutral or no emotion' or one or more of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that best capture the tweeter's mental state.
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