Task: Assess the emotional content of the tweet and classify 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 best represent the tweeter's mental state.
Tweet: “The #greatest fear #dogs know is the #fear that you will not come back when you go out the #door #without them.”   \n  ―#Stanley #Coren
This tweet contains emotions: 
fear