well, i don't equate it with falling standards, necessarily, but that's a semantic argument. i retain my sense of what's quality writing and what's not and all, but i suppose you could say they've fallen in the sense that i probably wouldn't be even willing to watch some things i do today.
also you might find it turns into a bit of a guilty pleasure, and makes watching some shows/reading some manga more pleasurable than others which may be better. especially when you turn to /a/ and there are tons of people spreading negativity even about manga that are pretty good, so if you're influenced by that type of thing, it's almost easier to enjoy manga you know are bad from the start. you don't really feel any need to try to find arguments for why it's a good manga(which you do if you try to discuss/argue for a manga's quality on 4chan).
it really started happening to me when i got fucking fed up with beat-around-the-bush retarded romances that took 26 episodes/100 chapters to develop into a simple confession and started reading a ton of hentai manga. believe me, it was refreshing; some of them actually have pretty entertaining stories.