Devin Faraci has a post on the pop culture nostalgia problem that is so good I don't think I can bring myself to just chomp any one piece out of it. Go read the whole thing first and then come back here.
You're back? Good.
The two things Devin nails about nostalgia: a) it is essentially narcissistic, and b) it crowds everything else off the table. Both of these are troubling for different reasons.
First, narcissism. That's a difficult charge to make stick — you could concoct an argument that anything that involves some attention to the self is a variety of narcissism — but the definition I'll use goes something like this: it's attention to the self that devalues both others and the self. When what you find yourself caring about most again and again is how something from your youth is being affirmed and respected, that becomes less about the thing itself and more about you having been right enough to be the one to love it.
I first ran into a version of this when talking about Grindhouse, where I noted two problems I had with the movie. A: what charm the grindhouse movies had was that they were executed on low budgets by people with few resources, and so they had to substitute ingenuity for budgets. To remake them on larger budgets is silly. (The trailers were more fun than the films themselves.) B: many of them were just plain terrible movies, and too much of the love for them seems to be more about remembering a time when such things were a regular fixture of one's moviegoing — in short, an attachment to the past. I wasn't interested in remaking what had come before (Hobo with a Shotgun); I was interested in how the lessons of low- and no-budget filmmaking could be applied to entirely new things (Upstream Color).
The second big problem with nostalgia is how it contributes to crowding everything else off the table. This is a common complaint of mine, one rooted in the same abuse of human psychology as junk-food manufacturers. It's not that I hate The Avengers, it's that I'm tired of every single upscale movie being made in the same increasingly generic action-beat vein. But they've found that's the easiest thing to sell, and so they make more of it because it means less pitchwork. Taken far enough, the end result is that much less to sell in the first place. Part of me isn't surprised that one of the recent big hits amongst the Gamer Generation has been Ernest Cline's Ready Player One, which is all nostalgic impulse (and, from what I've seen, little else beyond that). It feeds the whole mindset that anything from the past is as good as, or better than, anything the future could hold.
The more we look back over our shoulders, the harder it is to see what's around us, let alone in front of us.