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: @Mysteri759 @Ren102e906 @slb42jcb @swoozyqyah Well, I'm too old, and too stubborn about facts &amp; history to be discouraged.
This tweet contains emotions: 
anger, pessimism, sadness