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: Remembering those day when u still did'nt know kpop n thinking about how sad your life was without it - Kpop fan
This tweet contains emotions: 
sadness