Task: Classify the mental state of the tweeter based on the tweet, determining if it is 'neutral or no emotion' or characterized by any of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust).
Tweet: As I remember and reflect on Reginald Denny on a night much like this (like #Charlotte) I think to myself, the gun lobby must be rejoicing.
This tweet contains emotions: 
joy