Read this: Metallica's Lars Ulrich details how rock'n'roll ruined his life (not really)
Discussing the snare specifically, the drummer then recalls a "super-impulsive" moment from the studio.
"We were working on a riff," he remembers. "[Frontman James] Hetfield was playing a riff in the control room. And I ran up. I was, like, 'I need to put a beat behind that.' I ran into the tracking room and sat down and played a couple of beats over this riff to not lose the energy of the moment, and I forgot to turn the snare on. And then we were listening back to it, and I was, like, 'Wow! That sound kind of fits that riff, and it sounds weirdly odd and kind of cool.' And then I just kind of left the snare off for the rest of the sessions, more or less. And then it was, like, 'Yeah, that's cool. That's different. That'll fuck some people up. That sounds like that's part of the pummelling,' or whatever.
"And then it becomes this huge, debated thing. And sometimes we'll kind of sit on the sidelines and go, like, 'Holy shit! We didn't see that one coming,' in terms of the issue that it turns into."