Task: Determine the prevailing emotional tone of the tweet, categorizing it as either 'neutral or no emotion' or as one or more of the given emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that most accurately represent the tweeter's mental state.
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