Jesus' Son does great things with its titular character, the mysteriously unnamed Fuckhead. He is immensely likable - check out that winning smile and the off-kilter, observant humor - but his behavior is reprehensible. He is an idiot, but the kind of idiot who you're so close to that you want to help them rather than condemn them. The movie plays with your feelings toward FH, engaging you in a rollercoaster of frustration and pride. And when he gets hurt, it's like a punch to the gut. Billy Crudup's performance, in this way, is really remarkable. He oozes charisma and fun and gentle idiocy to the point where this film becomes a vignette in the life of that crackhead idiot you love to talk to at parties.
Also notable is Samantha Morton, in a stunning, indelible performance brimming with risk. Michelle is a completely ugly character, but Morton sells her appeal against all odds.