The reason this scene works for me is the distance between expectation and execution.
Walter expects to be able to make a great eulogy but fails, instead of a dignified urn they use the Folgers can and instead of the wind scattering Donny’s ashes out over the ocean, it blows them back into Walter and the Dude’s faces.
There’s this constant tension, where things are set up in one way but unravel and collapse under their own weight due to circumstance and incompetence — wrapping up in a completely different and ultimately more dissapointing way than the way they were expected to.
On one level, the whole film is driven by this dynamic, and the reason this scene works so well — and works by itself, even if one has never watched the rest of the film — is because it presents us with a distilled version of that narrative/thematic mechanism.
