I know that the gratitude will not last, because gratitude can never be a chronic emotion. I will forget the pain within the week and take my painless toe for granted again. But still the episode illustrates the point that suffering is necessary for the full appreciation of life. Without some experience of it, we could hardly be aware that we were enjoying anything; and it is why it is so difficult to imagine heaven, where suffering does not and could not exist. We can all imagine, vividly, a thousand hells, but a single heaven is quite beyond our imagination to conceive. That is why the iconography of hell is varied and fascinating, that of heaven dull and boring.
Not only the capacity for but also some experience of suffering is necessary, then, for the enjoyment of life: suffering in general, but not any particular instance of it, which should always be relieved if possible. This is nearly, but not quite, a paradox, which in general we misunderstand, to our own detriment.
— Theodore Dalrymple, “The Pain Principle“