 The music , philosophy and lifestyle of heavy metal bands and fans were often panned by both left @-@ wing critics and conservative public opinion , described as senseless , ridiculous to the limit of self @-@ parody , and even dangerous for the young generation . The 1984 mockumentary This Is Spinal Tap addressed many idiosyncrasies of British metal bands , showing comic sides of that world which external observers would judge absurd . Instead metal musicians regarded the movie 's content as much too real . 
