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