Epistemic status: playing devil's advocate.
Fiction is not a lie, but it is a variety of untruth. It absorbs time and energy which could be spent on fact. Although we make a conscious distinction between fictional worlds and reality, we will often use fictional examples when evaluating real-life situations. It has been argued that we should learn to take joy in the world we actually live in. Why should we allow fiction to warp our view of reality?
Perhaps fiction offers a fun, relaxing break. I can understand this claim in two different ways. The first version is that reading fiction gives us a rest from serious thinking, restoring us in some way. So, is this really true? Often when we feel tired of thinking, we're really tired of thinking about some particular thing. We gain new mental energy when we switch to something else. We think this means we're unable to do productive work, and need to take a break; but often, we could continue to be productive on a sufficiently different task, which gave us the same variety as a "break" would. (This is anecdotal. I recall seeing a discussion of this in a lesswrong post, but didn't figure out which one.) Alternatively, if we really are exhausted, reading fiction might not be restoring our energy as much as taking a nap or perhaps meditating. In either case, the pro-fiction argument seems murky. Answering this question is difficult, because it's far from obvious why certain types of thinking seem to take "mental effort" and leave us feeling drained. (It seems it might be a mechanism for sensing high opportunity cost, or it might be due to depleting a physical resource in the brain.)
A second way to interpret this is that consuming fiction is closer to being an end, rather than a means. The joy which fiction creates, or the rich inner experience, may be a good in and of itself. Whether it's useful for restorative purposes or not, it's good that society keeps churning the fiction mill, because it's one of the things which makes lifeworthwhile. Some people will readily agree with this, while others will feel it's very close to advocating wireheading. At a recent LW meetup here in LA, one person argued that if you're going to enjoy living in some universe, it might as well be the real one. I suppose the idea is that we should seek to make the enjoyable aspects of fiction into a reality, rather than exercising shallow escapism. I'm not sure this view can be defended, however. If you've got something like a computational theory of mind, and believe that uploading yourself into a virtual world is OK, how do you draw a firm line between "reality" and "fiction" to say which kinds of experiences are really valuable and in which you're just fooling yourself? Is it a matter of a sufficiently detailed simulation, which includes other conscious beings rather than puppets, and so on?
Robin Hanson discusses the social value of stories: those who read fiction are more empathetic toward others, seemingly fooled by story logic into acting as if good behavior is always rewarded and bad behavior punished. Although clearly valuable, this gives me the uneasy sense that stories are manipulative control directives. I mayenjoy the story, but does that make me comfortable accepting control directives from this particular author? Or should we examine the moral character of the author, before reading?
To make our arguments stick, we've got to compare fiction to relevant alternatives. It seems to me that we can havealmost as much fun reading biographies, memoirs, and (entertainingly written) history as we can reading fiction... and all with the advantage of being real facts about the real world, which seems at least a little useful.