我有多不好我自己知道
[wŏ yŏu duō bù hăo wŏ zì jĭ zhī dào]
This can be understood as "How terrible I am, only I know". This user probably uses this name to express self-awareness about their flaws, and implies a modest, humble or even self-discontent attitude, suggesting a willingness for introspection or self-improvement while keeping these perceived negative attributes known only to themself