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: Seeing an old coworker and his wife mourn the loss of their 23 year old daughter was one of the saddest things I've ever seen 😢
This tweet contains emotions: 
disgust, fear, pessimism, sadness