I make a point of actively curating my subscriptions–it's easy to get lulled into thinking the whole site is garbage when it's really just a few noisy subreddits. As any subreddit with a clear topic grows large, there needs to be strict moderation or it will devolve into crowd-pleasing gifs/memes/jokes, upvoted by people who aren't engaged in the original topic, in which case I'll unsubscribe.