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: One of the great/horrible moments as a professor is seeing a wonderful student leaving your university to pursue his/her true passion.
This tweet contains emotions: 
joy, pessimism, sadness