I used to listen to System of a Down daily.  It was almost like a religious thing for me.  Cut to a few years later, and I honestly can't stand them anymore.  They write these ridiculous lyrics in an attempt to be really esoteric and subversive, but it's just total nonsense.  Whatever meaningful message they're trying to convey is just lost in their inane gibberish.  


On the other hand, when I was about 14-15 I hated any kind of metal with extreme vocals.  Thought it sucked.  Cut to me ten years later and while I certainly do enjoy clean vocals, I have discovered plenty of more extreme bands I love and listen to.