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: He's mixing it up pretty well..using that slider pretty affective so far #thebabybombers #yankees #offense
This tweet contains emotions: 
joy