Learn English – a good word I can use for the talking I do with theself in the mind

I don't know of a phrase where someone can so generically point out a flaw. In your example, I'd say human - nobody is perfect. Perhaps his weakness or limitation would fit here.

There are words for dramatic flaws.

An Achilles heel: a portion, spot, area, or the like, that is especially or solely vulnerable. It does not need to lead to his downfall; it connotes someone who is pretty damned perfect except for this one thing. "Tom Cruise has an Achilles heel" would be understood that way.

His Achilles heel is his quick temper.

Shortcoming, or foible would be understood as an understatement; if he's crazy, that's a major problem; to call it a foible before stating the flaw would be mildly sarcastic.

A tragic flaw in drama is a failing of character in the hero (someone of high repute/honor/etc.) of a tragedy that brings about his downfall. Regarding Hamlet:

He has exceptional qualities like graceful personality and popularity among his country that is eminent. His tragic flaw is his delay in action and irresolution...

Other expressions for this are simply flawed, or inadequacy.

The word invasive implies monitoring someone in the general sense.

The problem with social media is that it's inherently invasive.

ODO:

invasive

ADJECTIVE

1.1 Tending to intrude on a person's thoughts or privacy

So it's a little bit invasive right now, and we have no privacy.’
‘Data retention is an invasive tool that interferes with the private lives of all 450 million people in the European Union.’