Warning! The following contains major spoilers for A Star is Born. Proceed with caution.
One of A Star is Born's most emotional moments is between Bradley Cooper's Jackson Maine and Sam Elliott's Bobby. The two brothers have a complicated relationship in the film, in large part due to their conflicting feelings about their deceased father. After another row between them late in the film, Jackson exits Bobby's pickup truck and stands there for a moment, before confessing that it was Bobby he idolized, not their father. Jackson then goes inside and Bobby turns to look out the back of the pickup as he reverses. His eyes are welled up with tears at his brother's confession. It's an emotional and memorable moment and, as it turns out, basically unscripted, as Sam Elliott explained:
So one of the film's most emotional moments and evidence that Sam Elliott should get a Best Supporting Actor Oscar nod, was basically an accident. The actor only turned around and faced the camera behind him so he could back the truck out of the frame. Smartly looking where he was going (a great driving tip) and being present in the scene by responding emotionally to what Bradley Cooper did and said, helped Sam Elliott deliver a lasting image in the film.
This is also impressive because Sam Elliott only had a rough idea of what Bradley Cooper's character was going to say when he got out of the truck. So he improvised to a degree. He responded in the moment and welled up with emotion as tears pooled in his eyes to show Bobby's tough shell cracking upon hearing how much his troubled little brother looked up to him.
You might think that after this happy little accident, director Bradley Cooper would want to shoot the scene again with this direction in mind to try and add to it or improve upon it. But, as Sam Elliott also told Yahoo Entertainment, there was no need:
The emotion was raw and real and perfect the first time and Bradley Cooper saw that and didn't feel any need to force it with another take. As Sam Elliott says, that speaks to him as a director. He created an environment where the performances were natural and those sorts of moments, full of unspoken emotion, were able to shine through.
This shot in A Star is Born is incredibly powerful in the moment, but becomes even more powerful after the film's ending. I'm sure the emotional moment would only become more impactful upon repeat viewings. So often in life, the weight of things left unsaid can become so heavy that it is difficult to move forward. That Bradley Cooper's Jackson Maine gets to have this cathartic moment with his brother and tell him how he really feels ends their relationship in the film on a positive note and adds some sweetness to the film's bitter tragedy.