From "The Song That Connects Jackson Browne, Nico and Margot Tenenbaum/Browne wrote 'These Days' at 16. Now 75, he and some famous admirers reflect on his unexpected mainstay: 'If a song is worth anything, it’s about the life of the listener.'" (NYT).
Here's that scene from "The Royal Tenenbaums":
The song, written when Browne was 16, seems to be from the point of view of someone who's lived through many phases of life. It ends: "Please don’t confront me with my failures/I had not forgotten them."
The article quotes Jimmie Fadden, "a co-founder of the Nitty Gritty Dirt Band — which Browne briefly joined": "I don’t know what his failures were at that time — maybe it was his report card, or school credits or the authorities at Sunny Hills coming down hard on him. All these years later, it’s a perfect song for any of us in our 70s.”
