Task: Identify the primary emotion conveyed in the tweet and assign it to either 'neutral or no emotion' or one or more of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that best capture the tweeter's mental state.
Tweet: Why is it that we rejoice at a birth and grieve at a funeral? It is because we are not the person involved. ― Mark Twain
This tweet contains emotions: 
optimism