I've bought into that idea that it all comes down to intention. And I think you must be disciplined, and a stickler, and hold yourself to a higher truth, to try to make sure that your intentions are pure. And I suppose you can never be sure. We are such a tangled ball of confusion. And our egos get in the way and cloud our thinking.
And then of course, you must remember that "The road to hell is paved with good intentions." And it's easy to be misunderstood, even if you tell yourself that your intentions are good. And there are so many contingencies, and so many ramifications to any action. And what you thought was good and pure can lead to lots of pain and heartache and misunderstanding.
Purity may be another one of those chimeras we base a life on.
So yes, even the easy, simple rule is fraught. That's the way it works in this mad adventure. You have a compass, but it's unreliable... and every time you turn, the needles spin... good luck Pilgrim!