You'll Ruin It for Everyone is a live album by Crass recorded at the Lesser City Hall in Perth, Scotland, on July 4, 1981. It was released in 1993 on Pomona Records with the band's permission, and rereleased with different packaging in 2001.The album's title is taken from a comment made from the stage by Crass singer Steve Ignorant whilst trying to stop a group of skinheads in the audience from fighting.