It would be safe to assume that most gamers (if not all) consider the sewer levels in games a very hellish experience. We all have the foreboding sense that as soon as we enter a sewer, we will be faced with a plethora of aggravatingly powerful enemies, a wide variety of status defects, and an intricate gathering of mazes that will test our wits and wills to the point of throwing our controllers into the TV or smashing our keyboards with our fists. There is a comparison here between the games we play and classical texts written over 2000 years ago.
One of the best ways to present the value of video games as art forms could be that of seeing the similarities between other art forms that have long established their legitimacy, and in that light I would like to present the similarity between the struggle of us gamers and the strife of the epic hero. The descent into the underworld, as it is presented in Homer's Odyssey, or Virgil's Aeneid, takes place towards the middle of the classical epics, and is a test of the heroes' vigor and will in their continuation of their quests. Throughout their experiences in the underworld, both Odysseus and Aeneas gain a certain fervour in the pursuit of their respective journeys. This influence can be seen overtly in the God of War franchise, as Kratos incessantly visits the underworld in every single one, and gains strength in his cause after his departure. The more subtle influence of this tradition is in the sewer levels in games such as Dead Island, Final Fantasy (VIII, XII), Vampire the Masquerade: Bloodlines, and so on. The seemingly arbitrary construction of mazes and frustrating enemies adds a certain unbearability to the games, yet the purpose of the developers could be to put us gamers through our own respective underworldly experience in order to further strengthen our cause.
At this point the question we should ask ourselves are these: After the completion of a sewer level, aren't we infinitely more relieved? Isn't the feeling of relief and satisfaction exponentially greater, the worse the sewer level is? After a slew of difficult enemies and the lack of useful loot, aren't we that much more excited to pursue our quest to it's completion?