'That is devilish unkind!' he said. 'I mean no harm - only to keep you from failing.'
Even if you mean no harm at all, you could still overstep someone's boundaries.
It should also be noted that chronic liars mean no harm and most of the time they do it unintentionally.
The manifestations of allergy—sneezing, wheezing, itching, and rashes—are signs of an immune system running amok, attacking foreign invaders that normally mean no harm.
