A music genre that you used to love but now you hate

Same for me.

None. There isn't any music that I used to like that I no longer like--even artists, albums, etc. I seem to be a relative weirdo in not "growing out of" any music, so it's difficult for me to relate to what that experience must be like.

That's a genre I'm not even familiar with.  Does WWE have composers who write that stuff just for the WWE?

Dude seriously shut up with that shit. I’m not sure why you feel the need to put down metal fans everytime the genre is mentioned. Why can’t you just say “I don’t like metal” instead of “I don’t like metal. By the way if you’re an adult and you like metal you’re retarded because it’s music for kids”? If you really think all metal is immature crap for kids then you’re totally clueless about the genre.

If you’re doing this because you like to get a rise out of metal fans because “it’s so easy to piss off metal fans”, then I’ll just say I’m sure most passionate music fans would get annoyed at some point if most people constantly said their favorite music was immature crap for kids. Ignorant morons are constantly putting down metal when they have no idea just how vast and diverse it is, it gets annoying at some point. It’s easy to piss off metal fans because the music they like gets unfairly and ignorantly shat on all of the time. No other genre gets shat on as much as metal.

If we're going to judge genres based on whom it was aimed at, then The Beatles are just as mature as metal given that they started out as bubblegum pop aimed at pubescent girls.

Yes, in a sense, metal's primary target audience is angry/frustrated alienated/outsiders, and there just happen to be MANY such people during adolescence. But I think this is only so because metal's primary (superficial) tone is aggression, which translates easiest to the emotion of anger, which might naturally appeal to angry people.

However, music is not all about primary tones and what emotions they evoke. I grew up hearing my dad play rock music on drums. I developed an interest in rock in my early teens and took up guitar. From there I started randomly exploring many rock genres and metal just happened to be one of them. What really kept my interest in metal, even above and beyond the majority of rock, was that it was far more consistently interesting musically, from both a compositional and instrumental standpoint. It's a similar thing I love about prog rock, jazz, and classical; and though much of jazz and classical is/was beyond my ability to play, I could admire the talent. Metal was a real "sweet spot" for me in that it challenged my ear and ability but wasn't beyond my grasp. So for me, the musical content alone (rather than the tonal quality) is what's kept me interested in metal, and it's the same thing that made me quickly lose interest in punk rock; which is very similar from a tonal standpoint, but totally opposite from a musical/instrumental standpoint.

So I think when you talk about people "maturing beyond metal" it really depends on what you're talking about. I might agree that many, for whom metal's only interest was its tonal quality, mature beyond metal (which is really saying nothing more than their emotions change and they find themselves attracted to music with different tonal qualities); but there's more than one way to "mature," and I find there are many, many metal fans who appreciate its musical qualities without caring too much about the tonal aspect. I'd even add that many of metal's biggest bands--Iron Maiden, Dream Theater, just to name two--are not primarily about aggression at all, that they encompass a lot of tonal qualities despite being within the metal genre. And I think that, after a while, with certain bands, the tone becomes so monotonous that it reaches the point of abstraction, meaning that the music is about as "aggressive" as, say, a construction site. Meshuggah is a band that does that for me; superficially, most would hear aggression, but for me they're so monotonous on this level that it becomes, much like classical and jazz, just pure music--almost completely about (in Meshuggah's case) the complex rhythmic quality than anything else.

No the fact is you haven’t really/seriously listened to metal in about 30 years, so you have no idea how much the genre has evolved and matured.

You know how I know you know absolutely nothing about metal today? Because you talk about the genre like it’s angry music for angry people yet there are shit tons of “happy” metal bands out there. Hell, most of the power metal subgenre is super happy and cheerful. The kind of music that would piss most angry people off. Not a great subgenre, but there’s some good stuff.

That is not true.  That is hardcore and deathcore stuff maybe.  A few subgenres that the younger crowd enjoys but you can't say that's what metal is about as a whole.  Half the metal shows I go to are filled with 40 and 50 year olds.  There may have been people that stopped listening to metal but that is wrong to suggest that people's tastes mature and they grow out of it.