I don’t know man, here was Walter, under enormous stress, desperate to
keep the company afloat, to maintain his family’s economic wellbeing, and to keep his pride intact, to the point that he’s spending his Christmas Eve prostrating himself before an arrogant, demeaning Miles Finch.
And Walter’s son destroys all his effort and humiliates his father, destroys everything his dad has worked for, all because Buddy refuses to just obey and sit still and be quiet and let Walter work for two minutes.
Maybe the whole movie works as a subtle commentary on how children will never appreciate nor understand nor acknowledge the sacrifices their parents make for them. From Buddy’s perspective, he can just run away for a half hour and then sing a song and everything he’s just done to destroy his dad’s life is fine and forgotten.