Task: Determine the dominant emotion in the tweet and classify it as either 'neutral or no emotion' or one of the eleven provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust).
Tweet: @Groupon_UK who do I contact about a shocking experience with Clear Sky Holidays booked through you guys?? #customerservicefail
This tweet contains emotions: 
anger, disgust, sadness