Back in December of 1996, worried about the influence of Green Day’s “explicit” fourth album, Insomniac, on her 8-year-old son, a mother decided to write a slightly aggressive letter of complaint to the band. It clearly hit a nerve, and she soon received a handwritten response from then-24-year-old frontman Billie Joe Armstrong. Both letters can be seen below.
Source: http://socynical.tumblr.com