Punna, there are forms recognizable by the eye that are desirable, lovely, agreeable, pleasing, sensually enticing, tempting. If a Monk does not seek excitement in them, does not welcome them, and does not remain holding to them, excitement is eliminated in him. With the elimination of excitement, Punna, there is the elimination of discontentedness, I say.

There are, Punna, sounds recognizable by the ear…, odors recognizable by the nose..., flavors recognizable by the tongue..., physical objects recognizable by the body…, mental objects recognizable by the mind that are desirable, lovely, agreeable, pleasing, sensually enticing, tempting. If a Monk does not seek excitement in them, does not welcome them, and does not remain holding to them, excitement is eliminated in him.

With the elimination of excitement, Punna, there is the elimination of discontentedness, I say.

(Reference: SN 35.88)

In this Teaching from Gotama Buddha, he shares a similar Teaching as the prior Chapter adding a bit more information.

The mind will experience desirable, lovely, agreeable, pleasing, sensually enticing, and tempting forms that the mind sees through the eyes. If a Practitioner does not long or yearn for excitement in these agreeable forms, welcome them, or remain holding on to them, then the mind can eliminate its craving/desire/attachment to impermanent conditions that are creating the impermanent pleasant feelings causing the mind to be dissatisfied (i.e. discontent). Because the pleasant feelings are based on impermanent conditions and are not permanent, the mind eventually becomes discontent or dissatisfied with the constant struggle attempting to hold on to the pleasant feelings permanently. While the mind experiences temporary pleasantness, it will eventually swing to painful feelings or feelings that are neither painful-nor-pleasant due to the mind basing its inner feelings on impermanent conditions.

Through the elimination of craving/desire/attachment for desirable and agreeable forms, sounds, odors, flavors, physical objects, and mental objects through the eyes, ears, nose, tongue, body, and mind, a Practitioner will gradually eliminate all discontentedness.

The unEnlightened mind will continue to long with a strong eagerness for pleasant feelings through The Six Sense Bases and as long as the mind is seeking, welcoming, and holding on to the cravings/desires for these pleasant feelings chasing after the objects of its affection, the mind will continue to experience discontentedness including painful feelings and feelings that are neither painful-nor-pleasant.

The mind needs to be trained to be “satisfied with what is” rather than continuously chase after the objects of its affection to experience pleasant feelings. Allowing the mind to continue to chase after pleasant feelings is to invite painful feelings and feelings that are neither painful-nor-pleasant into the mind.