The title track from Black Sabbath's best and most popular album (which sold over four million copies), "Paranoid" was a minor singles-chart entry upon its initial U.S. release in 1970, not even cracking the Top 60, but has since grown in stature (partly with the help of album rock radio) to become a heavy metal standard, to the point where it was even used in American television commercials nearly three decades later. It was an immediate success in Britain, however, reaching the Top Five in 1970 and even re-entering the charts in 1980, making the Top 20. "Paranoid" is easily the most concise and up-tempo song on the album (and perhaps in the group's entire Ozzy Osbourne-era catalog -- in both categories), and while it isn't complicated, it does take surprising stamina for a band to maintain its relentless, morose intensity. After the intro riff (which is never repeated), the main body of the song is built around a simple riff consisting of three power chords, adding an additional fourth when the song changes sections. The rhythms are chugging, pounding, and squared-off, with nary a trace of the blues-rock feeling that informed some of the band's work; this is unmistakable, straight-ahead heavy metal, pure and simple -- and simple it is, too, which really only serves to increase the power of the band's delivery. That's especially true for bassist Geezer Butler, who always provided a driving underpinning in all the band's songs, and whose lines here alternately play around Tony Iommi's riffs or mesh with them in unison to create the feel of an hammering, unstoppable juggernaut. Ozzy Osbourne's vocals, meanwhile, almost threaten to fall behind the band's relentless pace at times, but he wails the lyrics with the urgency needed to sell the performance, and the occasional raggedness only serves to increase the intensity, as though the band -- and thus the song's character -- could fall apart at any moment. The social and psychological isolation of the protagonist is apparent throughout the song: he self-defeatingly pushes others away even as he yearns for support; he indulges in aimless fantasies without finding a positive direction that really fulfills him; he wallows in self-involved depression and concludes that "happiness I cannot feel and love to me is so unreal." It's melodramatic, to be sure, but it also connected with countless alienated teenagers seeking expression of their anxieties, with enough extravagance to reflect the real-life intensity of those anxieties, but with just enough pure theatricality to allow distance and escape from them as well. That's probably the best explanation available for the song's enduring appeal, and it's a huge part of the reason that Black Sabbath continues to influence countless metal and alternative bands -- not filtered down through second or third generations, but directly from the original sources.