Can people (without some sort of drastic life changing event) change who they are past a certain point-say early twenties or so?

In NYT magazine a few weeks back there was a review of a book about PBO's Mom. The author describes their life in Indonesia in which PBO was verbally and physically harassed by Indonesian school kids and didn't respond. Someone asked his mother wasn't she gonna do something and she replied "Oh no. He'll be ok. He's used to it".

So if a refusal to get mad, take offense or start swinging back is deeply embedded in the man and he's mostly seen that approach work thru life, can he change at this point in his life? Would he even know how?


"When the snows fall and the white winds blow, the lone wolf dies but the pack survives."
Winter is Coming

Now this is the Law of the Jungleā€”as old and as true as the sky; And the wolf that shall keep it may prosper, but the wolf that shall break it must die.
As the creeper that girdles the tree-trunk, the Law runneth forward and back; For the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack.