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: @Uber_RSA when you click over and over again for a cupcake but there are no vehicles available... #sadness
This tweet contains emotions: 
pessimism, sadness