Magus recently started a topic over at OB, which I've really enjoyed reading so far. The title pretty much says it all, but the actual topic is derived from an article that Magus was reading about this very subject.

Without re-creating the topic here, I do want to post a quote from said article that Magus presented:

Zach Logan @ Toonzone:
"What I am deriding here is the general attitude of the anime fan. This is what is destroying the anime you love, both here and in Japan. Fandom too often gets embroiled in its own inflexible and unnecessary arguments. People often get wrapped up in their own community’s culture for a given series that they forget people on the outside may be incredibly turned off by this kind of behavior. Because the Internet is cut off from actual reality, those fanatics forget the impression they may be making on those who come upon their posts or rants. Fiercely dedicated fandom has simultaneously kept anime alive while being an accomplice to its downfall."

Click here to see the full topic.

I would say that hardcore fans have not stopped me from watching a particular anime or playing a particular game, but I have been a bit reluctant to watch certain movies or TV shows on this basis. Generally fans haven't actually turned me off something (because I can like it independent of what anyone else thinks), but there are definitely times where hardcore fans can make me a bit reluctant to try something out in the first instance - although as I said, this seems to be especially true for TV shows or movies. I'm not sure why that is; with TV shows, for instance, I tend to rely heavily on word of mouth because I am not a big TV watcher.