Task: Categorize the tweet's emotional expression, classifying it as either 'neutral or no emotion' or as one or more of the specified emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that reflect the tweeter's state of mind.
Tweet: The word happiness would lose its meaning if it were not balanced by sadness.
This tweet contains emotions: 
anticipation, joy, optimism, sadness