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: 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