The interesting thing is that Schopenhauer takes it a step further with his distinction of pain and boredom. While pain can be constant and ever-present (it’s a call to action, so if you don’t respond to it, it persists), pleasure (or a similarly good feeling) isn’t and turns into boredom if you have everything you need (if it didn’t, survival would be out of the question).
The reason of this is that each of these two poles stands in a double antagonism to the other, external or objective, and inner or subjective. Needy surroundings and poverty produce pain; while, if a man is more than well off, he is bored. Accordingly, while the lower classes are engaged in a ceaseless struggle with need, in other words, with pain, the upper carry on a constant and often desperate battle with boredom.”
“The most general survey shows us that the two foes of human happiness are pain and boredom. We may go further, and say that in the degree in which we are fortunate enough to get away from the one, we approach the other. Life presents, in fact, a more or less violent oscillation between the two.