Why the rudeness?

I was listening to Jhini by Indian Ocean today..how I love their music, and was reminded of a 'civilised' arguement I'd had sometime ago with an obnoxious "I am far better than you, you suck" kind of female. My trainer was going back to the US and since she liked Indian Ocean, we (all the trainees) had decided to gift her a CD of Jhini. Now, Ms Nose-up-in-the-air wasn't exactly part of the gang, infact, was a friend of another, who'd decided this farewell was the time to multitask, and had decided to invite her too . Not that I actually have anything against people gatecrashing other people's get togethers but I do like them to remember their manners; yes, the same manners that we're taught right from when we're still dripping saliva off our toothless mouths. Hmm..I must stop digressing so much..so back to the female and her manners. All of us (the ones who actually were a part of the farewell) were chit-chatting and generally having a ball of a time, and IH(our trainer) decided to finally open her gift. She, ofcourse, was extremely thrilled, and we were feeling nicely compensated by the happy look on her face, when miss uninvited decides to pitch in with her two bits in the rudest tone I have ever heard on a person till date. And what might her two-bits be, you may ask, and I shall tell you. So she goes "Let me warn you, this album is crap, Kandisa is the good one." While the rest of us are still trying to get over this gross trespassing of social norms, I say, "Well maybe, but it depends from person to person, I for one quite prefer this one over Kandisa" This wasn't the response she was expecting, so now(though I hadn't thought it was possible) in an even ruder and 'thou shalt not argue with me' tone, she says "I don't know how you can say that, I'm like the biggest fan Indian Ocean has ever had,have listened to every album of theirs so I'm quite an authority" Me wanting to avoid unpleasant sits just ended it by suggesting we could let IH decide for herself; and there ended one nasty discussion.
You might think"aah, so she wanted to bitch" and I say yesss *evil grin* ofcourse I wanted to bitch. I mean she was mean for no reason at all. Everything she wanted to say could have been said in far nicer ways. But anyway, that is not what this post is about, so I will lick my wounded ego later; what I'm actually trying to figure out is why should someone who's a 'fan' be considered an authority on things like books and music. One hears people saying it all the time"I'm a fan , so I should know", my point is you're a fan, so you would be more inclined to like it even before you evaluate it. It takes a person who's views are not already biased to be able to give an accurate evaluation of anything, be it music, books, or just about any situation one might come across, and something like that is best left to the experts. For people like us, who are not the experts, but have opinions nevertheless, why should we ever forget that what we have are just that: opinions.
Opinions are subjective, vary from person to person, and one person's opinions are not to be forced down another's. Which brings me to the other reason I disliked that woman so much, and people like her. It doesn't cost money to be nice to people. And yes I know its all about being real and saying it like it is. But saying it like it is doesn't have to be done rudely, one doesn't have to be a general nuisance in company to be real. It irks me because I find more and more people believing that is the way to go. Yes, the ruder people are, the easier it makes things for them, most people, including me, just let the rudeness go by, and let those people have their say so that it avoide further unpleasantness at the moment, but later, once its all over, it leaves a very bitter taste. I know its true for me, and for quite a few people I know, these incidents remain glued to our memory forever, it demeans the entire point of being nice to others. It demeans basic principles some of us live by. Principles like greeting people with genuine smiles, like making sure we don't hurt others by even seemingly rude statements, like believing what goes around comes around, and therefore making an effort to genuinely be nice even to people who might not do the same by us.
Its not difficult to not pepper everything one says with caustic remarks. Its not difficult to smile at people and its definitely not difficult to remember a little grace, a little smile, and a little consideration for other people's feelings not only make another person's day ,it goes a long way in making oneself feel good. I just wish more people would realise that.