^^^ Both are great parts, though Mustaine comes off as kind of whiney and "poor me"-ish. Great musician, but he was kicked out of the band because he was drunk all the time. Get over it, dude. Of course it is kind of ironic that years later Hetfield left temporarily because of the same thing. 
I also thought it was interesting, and very true to life, when Lars is giving James shit because of his recovery schedule. To a person in addiction recovery, their recovery schedule is essential. You have to be selfish because recovery is your prime directive above all else, including family, friends and business, or it's doomed to failure. And Lars' reaction, how Het's schedule angered and irritated him, I saw that stuff all the time from clients' families and friends. It's not a wrong reaction; it's natural to be angry when you have to bend your own life to accommodate someone who got themselves into Hetfield's mess, but that he wasn't as understanding as he could have been actually made me dislike the little Danish prick a bit. 