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: Sometimes, you have to smile, pretend everything is okay, and just walk away.
This tweet contains emotions: 
joy, optimism, sadness