Wu Ming has been holding back things since he was a child, and he also likes to hold back big things when he encounters them, because he feels that he cannot let others know, even those close to him - so what if he knows? I have no power or influence, so it is better to live in peace and contentment without causing more troubles to myself.
However, when Wu Ming grew up to be a weak-minded young man, he suddenly felt that bullying others with power was indeed a relief - especially when the people who had bullied him were bullied again.