Let me start by saying I suffer from an overactive brain.  Few things please me more than my ability to over-analyze things, and I recently did this with the concept of fandom.  I'm being general here, and am NOT saying it's always like this, or that everyone is the same.  These are just some theories based on general observation.  I find fandom to be kind of a strange, and touchy thing, and here's why:

#1 - Our bias runs deeper than we think.  

Often times, when we become a fan of someone, it becomes a wonderful, exciting thing.  We suddenly want to share that person's talent with everyone.  But the more hardcore we are about who we idolize, the easier it is for us to subconsciously (and unrealistically) expect everyone else to see our idols as we do.  Somewhere in our brains, we already know that not everyone will like them, but it's often overridden by the part that loves the idol(s).  So when someone else sees them and points out that they don't feel this person is talented, we're always shocked, often offended, and sometimes hurt.  We feel a sense of disappointment that not everyone can see our idols through our eyes.  Then other times, when someone expresses interest, we suddenly want to show them EVERYTHING this person has done, and share our knowledge.

#2 - Many fans are ok as long as reality doesn't hit.

When it comes to idols of the opposite (or same , depending on your preference), there is one concrete reality nearly every fan must face:  "I don't have a chance."  From what I've seen, nearly every fan in the world has their own fantasies about being with whomever they idolize, and that's perfectly ok.  For some fans, as long as they stay immersed in these fantasies, everything is okey-dokey.  But once that bubble is burst, and they realize their fantasies will most likely never happen, they sometimes fall apart.  It suddenly becomes difficult to maintain a one-sided love, and some people even abandon their idols out of heartbreak.

#3 - The fragility of the idol image.

I've noticed over time, that a LOT of fans forget that idols are still human beings.  They make mistakes.  They say things we don't want to hear.  They do things they shouldn't.  They have pov's that conflict with our own.  A lot of fans build up the proverbial pedestal quite high, then place their idols at the top.  Then suddenly, the idol does something utterly human, and people feel the need to kick that pedestal down a few notches.  Some even remove the pedestal completely, and walk away without so much as a backward glance.  We become so used to seeing only the best things about them, and relying on their camera time to be an accurate measure of them as a person, and this just isn't always so.

#4 - Jealousy.

Because it's soooo easy to develope strong emotions for our idols, it's also easier in turn to become jealous when they like someone that isn't us.  When it comes to k-pop boys, fans love seeing them so comfortable and touchy-feely with fellow members, or other male stars.  Yes, it's fun, smexy, and cute to behold, but I get the impression that some of the underlying cause is because a lot of fans are more comfortable with the idea of losing their idols to another guy (preferably someone in the same group), than losing them to another girl.  When another girl gets involved, jealousy springs up from everywhere, to the point where fans will even start bashing the girl of our idol's interest.  Suddenly, this can be tied right into issue #2 above.

I posted this not only because these are things I've seen happen quite a bit, but also because I'm guilty of them as well when it comes to my k-music idols.  With many of them, these were all things I experienced, but I came to my senses, and I like to think I'm much less ignorant now, and have a better understanding of how the idol-fan relationship works.  My theories and points actually reach even deeper, but this is long enough and I figured this was enough of a summary.  If you've read all this, I commend you.  Thanx for listening!