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: In inter-group relationships, #anger makes people think in more negative and prejudiced terms about outsiders.
This tweet contains emotions: 
anger, disgust, optimism, pessimism, sadness