My favorite thrash band from my youth, Sepultura, one of Brazil's most famous bands. There is a period that most highly talented bands experience, a sort of golden age. In their early years they put out an album or two, three in some extreme cases, where there is a lot of inspiration and creativity, but the band lacks polish, professionalism. Later in their career they put out albums that are polished and professional but lack inspiration and creativity. The great bands put out an album or two (three or even four in the most extremely fortunate cases) where creativity and polish intersect to produce something really special (e.g. Queensryche - Operation Mindcrime, Metallica - Master of Puppets, Rush - A Farewell to Kings, etc).
Anyway, here are a couple of track off Sepultura's 2 "intersect" albums: