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: No red card for Gordon there? The ref must be a Celtic fan as that was a shocking challenge.
This tweet contains emotions: 
anger, anticipation, fear, surprise