Why do some detest mainstream music only because it is mainstream?

I know this girl that only likes bands that no one else has ever heard of. There have been more than a couple bands that she liked when they were nobodies and she loved them. Then they get big and people start to recognize the name and she is like "ugh they are terrible" "they are sellouts" blah blah blah. It is annoying. I know a few people that are like this. While I dont like mainstream music just because it is popular i will admit I like about 60 to 70 percent of the mainstream rock music right now. Why can't people just enjoy good music and not get caught up in labels and how popular a band is?

It's hard to tell from your description if this girl really enjoys the music she listens to. I don't really listen to most mainstream music. It just doesn't appeal to me because it sounds so formulaic. However, Some good stuff slips through the cracks. Some people take this ideology listening to non-mainstream music and make it their mantra. Unfortunately, they tend to be very superficial and miss out on a lot of good stuff as a result.

as far as rock music goes, there hasnt been a decent mainstream band for years

because every one wants to be sooo different and soo "non-conforming" and sooo unique that they hate everything popular.

because they're just sooo hardcore.

EDIT - and everything the guy above me said.

I don't know much about rock music, but I can tell you that "mainstream" music really does tend to grow more and more commercial. Like the person above said, the "formulaic" aspect causes a lot of songs to sound the same and get old really fast. This leaves many with no chose but to seek less popular music that have not been commercialized. It is entirely possible that your friend used to like bands when they weren't known because they were more original. Often times when artists get big, they tend to change to conform to the demand of the industry. This especially happens a lot in hip-hop.

People do this for various reasons, but one that springs to mind is a person wanting to feel some sort of uniqueness. It's a way of setting themselves apart from the crowd if they are one of a smaller, dare I say, more select group of fans. They delude themselves into thinking they are better than one of the mindless drones that like something more popular. Once a band becomes popular the feeling of uniqueness falls away. Instead of transitioning to a feeling of community, the listener may become disillusioned and trash what they had championed before. It's very common, and kind of tedious. I don't mean to be label this person that you speak of, but it sounds like this is a repetitive reaction on their part, and I think this is a likely explanation.

they wanna feel important and be rebellious, that's why

Lots of people go through that, and if the band becomes popular, like Muse, they stop liking them immediately. It's just something we all have to outgrow.

I always get blasted by the Cult of The Orginal Metallica for saying how well constructed and moving a song "Hero Of The Day" is. I shrug, smile and don't care.

Whatever anyone likes is good music.

"Mediocrity shall always have the final word" -novelist William Heinesen.

Well, for the most part, mainstream music nowadays is just another band trying to sound like another. It's just not original. Plus, a lot of these bands sound great in the studio but, put them on a stage and let the garbage begin.There are so many bands out there who people don't even know about that they would probably love if their music wasn't force fed to them. All of the radio stations in America are owned by 2 huge corporate umbrellas who control what gets played. I don't knock anyone's music choice but, in my opinion, what you hear on the radio are not the best bands anymore.

Anyone who hates mainstream music simply because it IS mainstream are idiots who are trying to give themselves a fake "rebellious" persona.

However a lot of people hate it when bands change their sound wildly to appeal to a wide audience. This is pretty much justified, I mean to be fair it's always a bummer if your favourite band of <insert genre> starts playing generic pop music.

And on the flip side of the coin you have people who only listen to the radio and don't have a choice to like anything OTHER than the mainstream, I kind of feel sorry for these people myself, they are missing out.