The Big Bright World Songfacts says the song contains a lyrical sample from Dylan Thomas' poem Do not go gentle into that good night, which was written for his dying father. Originally published in the journal Botteghe Oscure in 1951, the poem's connotation with death and endings has been much used in film and television, including in the final episodes of both St. Elsewhere and Roseanne.
We are difficult to understand
It was hard to make the simple plan work
Difficult and that's what made it burn