The ultimate punishment of the wicked is a total separation from goodness and abundance, pictured as a flowing sweetness that remains forever out of reach. The primary approach among commentators is that this serves as a curse of absolute deprivation [שטיינזלץ]. Even when the world is filled with immense blessings, flowing powerfully like branching rivers and streams of honey and butter, the wicked will be entirely cut off from enjoying them [מצודת ציון, תקות אנוש]. No matter how much good surrounds him, he will neither see it nor taste its sweetness [רמב״ן]. Instead of drawing nourishment from this rich abundance, his portion is only ruin, left to consume the toxic venom of snakes [מצודת דוד].
Beyond physical deprivation, this lack of fulfillment is also understood psychologically. Even if a wicked person successfully acquires great wealth and worldly pleasures, he will find no true joy or peace in them. The sheer amount of pain, toil, and effort he invested to gain these comforts far outweighs any brief enjoyment. As a result, he never experiences a meaningful or happy reward for his hard work [מלבי״ם].
Taking these physical images as a metaphor, the flowing sweetness points to the highest spiritual rewards. The rivers of honey and butter symbolize the ultimate peace of the World to Come [תקות אנוש] and the beauty of the Garden of Eden [רש״י]. For the righteous, this takes the form of pure rivers of sweet oil revealed to them moments before they pass away. However, because the worldly suffering of the wicked fails to bring them atonement, they are forever denied the vision of this spiritual abundance [אלשיך].