A scorpion and a frog met beside the bank of a river and the scorpion asked the frog "Please Mr. Frog will you carry me upon your back across the river, for I have no other way to cross." The frog, wary of the danger replies, "How do I know you won't sting me, after all, you are a scorpion." The scorpion stated rather matter of factly, "Of course I will not sting you, because if I do, I surely will die too. After all, I cannot swim."
The frog, satisfied by the apparent logic of the scorpions response sets out across the river, scorpion on his back. Suddenly, midstream, the frog feels a sharp sting. Slowly, the venom coursing through his body, the frog feels the onset of paralysis and starts to sink. Knowing the scorpion has doomed them both to drown the frog only has the strength to gasp "Why?"
Facing certain death the scorpion can only reply "Because I am a scorpion, and it's in my nature to sting..."
The moral of this story has been interpreted many different ways. There is no malice, no anger, no real intention to harm, behind the scorpions actions. Only an indiscreet error leading to inevitable destruction. A virtue, not of the sharpness of the sting, but of the potency of its venom.
We all have a capacity to be the scorpion or the frog. To accept a risk of being hurt, and a risk of hurting others. Such is the complexity of all relationships. I've found that, though Buddhism provides the tools to know equanimity and loving kindness, regardless of practice, it is the nature of life that sometimes we become the frog, and sometimes we become the scorpion. Though we may strive to perfect ourselves, we are as yet unperfected.