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: Dear everyone at HSSU, stop walking with your phones up so I can smile and wave at you and you can smile and wave back :(
This tweet contains emotions: 
sadness