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: There will be no #gaming video today. An old friend of mine passed last night, so I'm taking some time to grieve. Thank you #StandUpToCancer
This tweet contains emotions: 
sadness