Hi,
Here are a few edits.
What has been on my mind
Well, there is actually not a lot on my mind. It is just that my son really pisses <<< this marks this as very informal writing - and even informally, note that this term offends quite a lot of people me off sometimes. First, I think he is neither like my wife nor like me. We always keep ourselves active in things we are working on. Instead, he lacks ambition to care about stuff around him, which nevertheless can be good for him. Moreover, it appears that only things like watching TV and playing on-line games can arouse his interest. At times I feel so frustrated being his old man, and I hope that he really thinks about how to improve his life as well as his school studies.
Best wishes, Clive