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: A #smile doesn't always mean a person is #happy . Sometimes it simply means they are #strong enough to face their own #problems .
This tweet contains emotions: 
joy, optimism, sadness