In an interview with Rolling Stone magazine, Metallica drummer Lars Ulrich said that super-producer Rick Rubin is influencing Metallica and causing them to rethink their approach to record making.

"He's questioning what key we should play in," Ulrich told Rolling Stone. "We've played in E flat since the beginning of the '90s. Nobody questioned it. All of a sudden, Rick is going, 'Maybe the stuff has more energy and Hetfield's voice sounds better in E.' He's forced us to rethink big-picture stuff, something we haven't done in years."

Lars has been considered one of the most stubborn men in Rock over the last 20 years.  What is it about Rick Rubin that makes him so influential.  The man has worked with some of the top bands and artists ever, and is responsible for reviving numerous careers.  I contend that fear breeds creativity.  Why would you fear Rubin?  Perhaps it is the fact that he looks like the bastard love child of Rob Zombie and Charles Manson.  If he had a swastika tattooed to his forehead, Metallica would be covering Helter Skelter as we speak.