Strip the meme away and the same insight surfaces in all three systems: what shapes you is not chiefly what lands on you, but the quality of will from which you act.
The Buddhist hinge. The Buddha's definition is almost startlingly psychological: "Intention, I tell you, is kamma. Intending, one does kamma by way of body, speech, and intellect." Karma is cetana โ volition. The same physical act, done from greed or from compassion, plants opposite seeds in the mind. This is why karma is not a tally of deeds but a training of the heart.
The Gita's hinge. Krishna's nishkama karma points the same way from another side. You cannot control outcomes โ only your orientation. Act because it is right, surrender the fruit, and the action no longer binds you. The Internet Encyclopedia of Philosophy frames this as duty done "without the motive of consequence."
The Jain hinge. Even here, where karma is literal matter, the binding force is inner: it is kashaya โ the passions of anger, pride, deceit, greed โ that make karmic particles stick. Cool the passions and the dust finds nothing to cling to. Three radically different metaphysics, one shared verdict: karma tracks the will inside the act, not a scoreboard of who wronged whom.