It was intense.
Bassist Jason Newsted left the band. James Hetfield was battling addiction. Lars Ulrich was in therapy and talking to former guitarist Dave Mustaine. Kirk Hammett's feelings are best expressed in the image on the left. The band was recording St. Anger and trying to find a bass player.
Pitchfork contributing editor Mike Powell wrote a great piece about the documentary. It's been ten years and Metallica is still rolling. Powell writes about the ongoing battle between Hetfield and Ulrich:
"But there's no point in being hard on James Hetfield, because, as the saying goes, nobody could be harder on James Hetfield than himself. Opposite him in this waltz is Lars Ulrich, their drummer. If Hetfield is a walking button, Ulrich is a finger, prodding at Hetfield with effortless, West Coast passive-aggression, stirring up small problems for fear of acknowledging the larger ones."
You should read Powell's full story and watch the documentary if you get a chance.