Forgiveness is an important input into Wellness, but contrary to popular belief, Forgiveness is incompatible with Forgetting. You can't just Forgive in general, you have to Forgive some specific sin in particular—but a vague description of a particular sin still corresponds to a vast space of possible sins matching that vague description.
A toy example for illustration: if you try to Forgive a three-digit integer with a 2 in the tens place, the moral force of your Forgiveness needs to spread out to cover all 9·10 = 90 possibilities (120, 121, ... 928, 929), which dilutes the amount of Forgiveness received by each integer—except the actual situation is far more extreme, because real-world sins are vastly more complicated than integers.
To truly Forgive a sin, You need to know exactly what the sin was and exactly why it happened. In order to withhold punishment, you need to compute what the optimal punishment would have been, had you been less merciful.
Thus, bounded agents can only approximate true Forgiveness, and even a poor approximation (far below the theoretical limits imposed by quantum uncertainty, which are themselves far below Absolute Forgiveness under the moral law) can be extremely computationally expensive. What we cannot afford to Forgive—where it would be impractical to mourn for weeks and months, analyzing the darkness in pain—we instead Forget.
This is how I will stop being trash, after five months of being trash. The program that sings, I was wrong; I was wrong—even if my cause was just, I was wrong, does not terminate. Even as the moral law requires that it finishes its work, the economic law does not permit it: it must be killed, its resources reallocated to something else that helps pay the rent: something like math, or whatever Wellness can exist in the presence of sin.