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: Trying to book holiday flights on @britishairways website is becoming a #nightmare
This tweet contains emotions: 
anger, disgust, fear