The sound guy has it rough... if you're enjoying the show, you're not thinking about the sound guy at all, but if the show sounds terrible, the entire club is suddenly very aware of the guy behind the sound board.
People complain about the sound guy a lot, and sometimes that's not entirely fair: not everything is the sound guy's fault. Some thing are-- some sound guys are as bad as the internet makes all sound guys out to be-- but they seem to get blame for just about everything... and there are an awful lot of people giving up their friday and saturday nights to get sound in the mains.