As always, after making a post that could make someone potentially very angry and arouse ire against me, I felt very nervous and a bit ill when I next went to look at the thread. Before doing so I found myself preparing some defensive response as to why I'd been so blunt, and potentially softening my response to mention that lots of people go through this stage of fanfic, of taking some story setting one really likes and making up some improbable all-powerful character to put in it. I did it myself, although mercifully I can only think of one or two instances when anything actually got written down. I detest this sort of fanfic but on remembering this earlier today (for the first time in years) I understood a little more of why people...kids, really...come up with this stuff.
Several years ago I learned a little bit about child development in the course of my student job as a childcare assistant. I knew people developed thinking skills and such as they grew, of course, but it was then that an example of the scale of this kind of development was given me -- how three-year-olds (give or take, of course) don't really have the concept of cause and effect then, or counterfactual reasoning, while a year later they do. Later on I found a suggestion that the tendency of teenage/young adult recklessness could be another developmental stage...the idea that bad things won't really happen to them. One could even consider this a survival trait, in that being too aware of how easy it is to die or suffer and that bad consequences could result from action could seriously hinder certain necessary behaviors - how many young soldiers would march off if they truly felt that they could and likely would die? I've never had much patience with the "it won't happen to me" attitude, even though I surely had it at least subconsciously (nowadays I tend to be the opposite, totally too imaginative about possible disasters to the point of being paralyzed with fear) but the idea that it's a mental stage similar to the child pre-reasoning stages we go through makes sense. We tend to think that by the time we're physically matured we're also mentally matured (emotionally being another matter), but there's no particular reason to assume so just because we're starting to look adult.
Likewise, today it occurred to me that what I generally lump together as bad fanfic (because it is) may well be a developmental stage. It certainly seems that I see it more with young teens than elsewhere, although since I try to avoid fanfic it's not really a representative sample. As to why, I'm not sure. I would hazard that part of it at least initially has to do with escapism and immersion, although I'm thinking more of daydreaming and putting oneself in the story (which didn't appear to be the case with the person whose idea prompted this). Another part is presumably the desire to create without knowing how to go about it, and hence piggybacking off of what someone else created...I want to be cool, this is cool, so I'll change enough of it to call it mine and then I'll be cool too, because I know this works and I don't know how to be cool from scratch. (Sorry for the overuse of "cool" but the example which prompted this musing used it rather a lot.)
I was going to try to analyze it more but my brain is shutting down for the night. Last thought on this is that it's not just fiction; there's surely a lot of fanart that would go into this category, though I'm inclined to put tracing/copying of official art in rather than original poses, clothing, etc.
P.S. My post so far has garnered only agreement, no flames yet. Probably because the idea person hasn't seen it yet...