The most effective way to hurt something/someone is through studied intimacy.
The "blunderer" is forgivable out of their ignorance: in the unlikely event they land a haymaker to your soul or sabotage your company it is by chance or luck.

The devoted acolyte who accessed the inner sanctum through devotion knows precisely where best to strike. In knowing the betrayal is doubled. It is no longer simply a devastating wound, but the loss of trauma support. (This is why family and partners can hurt us so profoundly.)