I just tend to be really picky about it, I think it might be the vocals a lot of Thrash Metal bands tend to go for, which could go some way to explain why I like old Metallica far more then new Metallica. Testament have done some stuff I enjoy and I quite like Trivium's thrashy stuff.
I missed my chance to see them live twice. Which sucks, because they're my favourite Folk Metal band. They're one of the few non Doomy or Blacky Folk Metal bands that aren't tongue-in-cheek, which is a nice change. (Even though I do love the less serious bands too.)