Task: Determine the prevailing emotional tone of the tweet, categorizing it as either 'neutral or no emotion' or as one or more of the given emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that most accurately represent the tweeter's mental state.
Tweet: Since the 'update' my @iPhone loses power nearly 40% faster.  #furious
This tweet contains emotions: 
anger, disgust, sadness