Music has been around for thousands of years, but we all just so happen to prefer the music that was made during our youth.
That's quite a coincidence!
Music is much more that an organization of pleasurable sounds. It's part of our identity. We form a sense of belonging from adopting the same music within our social group.
Bands have different social, cultural, and political beliefs. If we embrace those bands it means we stand for their beliefs. Bands have different images. Their hair, clothing, dance moves, and subject matter sometimes are even more important than the actual music itself!
It's common for kids to reject any music that is outside of their identity, regardless of how good it may be...They don't even give it a chance. (I was a "Metal Head" in High School, and I had to keep my fondness of disco completely in the closet for fear of being ostracized from my peers!)
And the last thing a kid who is asserting independence will do is listen to their parents music. In fact, the more the parents hate it, the more attractive it is.
"It's Not That I'm Old, Your Music Really Does Suck!"
Listen...I was a professional music producer before I got into Child Psychology. I know a lot about composing songs, recording bands of all types, and what musically works and what doesn't...But I'm not going to lie. The most popular music that kids listen to today...really, really, does suck!
"How can you say that?...It's a matter of personal taste!"
I enjoy music across all genres. Rock, Pop, Metal, R&B, Rap, Classical, Country, Gospel, Disco, even Jazz. But each one of these genres has some great songs, and has some terrible songs.
"So what makes good music good, and bad music bad?"
All a song has to do to be good, is move you emotionally. It doesn't matter if it's intense or tender. It doesn't matter if it's slow or fast, it doesn't matter whether it's complex or simple...It just has to take you on an emotional journey through sound. Much of today's music just does not do that.
However, some of it does, and It's important that your child listens to music that evokes emotion. Whether it's soft or hard, uplifting or soul crushing, stirring up emotion strengthens emotional intelligence and awakens imagination. Once your emotions are activated, you identify them, you explore them, and you learn about them. This process also exercises imagination. None of this happens when bland music leaves your emotions dormant.
"But just because YOU'RE not emotionally moved by it, doesn't mean they're not!"
Of course. But as long as your kid is being emotionally stimulated, whatever it takes to do that is fine. However, it can also be said that music is universal. You can take African beats from the Congo and play them for Nuns in a convent in Ireland, and those Sisters will be "breakin it down" like you never saw before! - Good music is good music no matter whose ears it falls upon. If it's rejected, it's usually because of a negative association...not the actual quality of the music itself.
Summary
Introduce your kids to music as early as possible. Make sure the music stimulates emotion and imagination. Provide a wide variety of different genres. When they are older, telling them that you think their music sucks may draw them closer to it, even if it does suck! If possible, try to find songs in their genre that actually grove and flow. And if you can get them to play an instrument, or create their own music, even better!