Now, I know we all vary on this list depending on the combination of personalities and series discusses, but it would be nice to understand how easily people get on each others nerves when discussing their favorite series. Just knowing what level you're at could be a great help in avoiding (and finding!) fights.
To that end, I propose the following 12 Levels of Comic Book Fan Agreement:
I. Your favorite series is my favorite series, for much the same reasons. -- This is the friendliest you can get. People on this level of agreement in geekdom tend to spend their days trading theories (in essay or fiction form), making series-pertinent jokes, and teaming up during arguments to overpower someone from a different level of agreement.
II. I like your favorite series, but for a different reason. -- There is a divergence, but its still friendly and in addition to all of the above activities, two fans on this level of agreement will debate their favorite aspects of the series, and try to win each other over.
III. Your favorite series is fun, but would be better this way -- There's potential for insult here, but as there is still a common ground between the two fans so this is a friendly level of agreement. This is the first level where the presence of fanfiction about the series becomes a modifier on the fan relationship, depending on how the new idea is presented and received. If the idea isn't well-received to begin with, presenting the change in fiction form can be an even greater irritant (conversely, if well-done it can win the other over). Since there's still a lot of common ground and goodwill, it tends to be only a mild irritation if its an irritation at all.
IV. I don't get your favorite series at all/I dislike your favorite series for my own perfectly valid reasons. -- While on the surface a perfectly viable argument, it can still hurts a fan a little bit when someone doesn't share her tastes. Its stupid to take it personally, but we are all fanatics. Different common ground can easily make up for this.
V. I like your favorite series, but only for a reason that grates on your nerves. -- This is where friendliness starts to break down, as every discussion of the series in question brings up the one part of that series that one person can not stand. They start to associate the other person with that one little annoyance, which leads to a foul relationship.
VI. I like your favorite series, but only for a reason that really grates on your nerves, and I write fanfiction based entirely on that reason. -- There's a chance that a well-written story can turn around someone's ideas on a concept, but in my experience that's pretty rare. Usually it just makes things much worse, and the two fans on this level should avoid each other.
VII. I don't like your favorite series, because I think it would be better this way, and I won't even bother to try it at all unless someone makes it that way. -- A reasonable disinterest or aversion after reading one issue/hearing the concept is one thing, but this is insulting because it insists on changing something that a person enjoys very much, just to suit someone's personal tastes. The problem here is that, if it were to be changed to suit one person, what the other person loved about it would be gone. Two fans who find themselves at this level of agreement had best find another subject to discuss.
VIII. I don't like or understand the basic premise of your favorite series, I've never read it, and I won't be bothered to actually read it, but I write fanfiction about it anyway. -- This should be self-explanatory, but here goes. If you enjoy something very much, and someone comes along with this attitude, insists they know better than you, and writes their desires in a fictional format (which, as we're discussing fictional series, only makes those ideas clearer and more solid to the reader) and has absolutely no idea what makes it desirable to you, it might get on your nerves more than someone saying "I think it might be better this way," "It doesn't interest me" or simply writing a "what if" fanfiction story that diverges greatly from the concept you love, but still has a basic love for what your loved.
IX. I don't get your favorite series at all/I dislike your favorite series for my own perfectly valid reasons, and you're a fucking idiot for disagreeing with me. -- Anytime someone gets snotty, things are much worse.
X. I think your favorite series would be better this way, I won't even look at it until its changed to be that way, and you're a fucking idiot for disagreeing with me. -- See the unfortunate mixture?
XI. I think your favorite series would be better this way, I won't even look at it until its changed to be that way, you're a fucking idiot for disagreeing with me, and I write fanfiction to demonstrate the rightness of my way. -- Stubbornness, snottiness, and those ideas made concrete by a fiction format. Bad combination.
XII. I think your favorite series would be better this way, I won't even look at it until its changed to be that way, you're a fucking idiot for disagreeing with me, and I write terrible fanfiction to demonstrate the rightness of my way with a thinly veiled self-insertion character, and a character from another series that I felt was fucked up unless written my way too. Oh, and if you think my fanfic is bad/un-entertaining/uninteresting/not as good as your favorite series, you must personally hate me and everyone who shares my interests. -- I think you all get the picture.
Now, did I leave anything out?