Appetite for Destruction. It was because when you added up the amazingly catchy songs, songs that had perfect pop appeal but sounded "organic" not studio light-weight pre-fab rock manufactured by Desmond Child or Mutt Lange, and the nasty 70s Aerosmith image at time when glam rock blow dried aqua-net dominated, well, they were the closest thing to an American Led Zeppelin (i.e., the Holy Grail) that we've ever produced. That's really what sent a shudder down the spines of American rock fans in 1988 - that even moreso than Aerosmith from 1973-1977, AC/DC in 1980 or Van Halen from 1978-1984, "Appetite" sounded good enough to think that there really was a possible second-coming of Zeppelin in terms of overall God-Like Rock Awesomeness. And it has stood up. I don't know if Appetite is the GOAT rock record. But I do know (IMO of course) it's the "Greatest Since" -no record released after it has been as good.