Task: Analyze the tweet's emotional connotations and classify 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 best portray the tweeter's mental state.
Tweet: The word happiness would lose its meaning if it were not balanced by sadness.
This tweet contains emotions: 
anticipation, joy, optimism, sadness