Why is there the phenomenon of "a sheng of rice brings gratitude, but a dou of rice brings enmity"?

When a person is first shown a small favor, in conscience they know to feel grateful. But when favors are bestowed upon them continuously, a habit of being the recipient of charity is formed; they enter a comfort zone, come to take it for granted, and develop dependence. When this sense of taking things for granted is broken—when others no longer give, the comfort zone disappears, and there is nothing left to depend on—they feel uncomfortable and cannot accept it psychologically, and thus hatred arises. It is very difficult to break a person's habits; not letting people become dependent will breed resentment. No one is willing to break their habits, especially habits of comfort and enjoyment. No one is willing to accept teachings that differ greatly from their own habits and views. If you want to change a person, you must do it slowly and gradually, and must not rush things.

Since habits have such adhesive power, one should strive to cultivate good habits in order to drive out bad ones. For example, if contemplating the breath becomes a habit, it will drive out scattered thoughts. When one is in the midst of random, disordered thinking, upon contemplating the breath, all of the manas's energy concentrates on the breath; meditative concentration (samādhi) appears, and the scattered thoughts disappear. It is the manas that gradually adapts to receiving favors, forms habits, and develops dependence. The manas has great greed and inertia: forming bad habits is easy, but changing them is very difficult; accepting favors is easy, but losing benefits is hard to bear.

Which mind feels gratitude? Which mind turns to enmity? Love, hate, affection, and enmity all depend on which level and degree they fall into—whether they are genuine or false, how genuine, and how false. Emotions that are relatively deep belong to the manas; those that are relatively shallow and have not yet formed habits belong to the mind consciousness. At the stage of the mind consciousness, emotions are all easy to regulate; once they fall into the manas and form habits, emotions are no longer easy to control.

When receiving a favor, anyone with a bit of conscience will have a grateful heart, keeping it in mind thought after thought, thinking of repaying it when they have money—both the mind consciousness and the manas are like this. If the mind consciousness must constantly remind the manas to be grateful, it shows that the manas has no conscience; a person with a conscience does not need reminders from the mind consciousness. It is like a person whose mind consciousness has realized the fruit: they need to remind the manas at every moment not to have afflictions, not to be attached to the five aggregates (pañca-skandha), that the five aggregates are false. But when the manas itself realizes the fruit, there is no need at all for the mind consciousness to keep reminding it; the mind consciousness need not speak, need not keep reciting that the five aggregates are illusory—the manas knowing it is enough.