A shotgun shack is a tiny, tiny, crudely built house.
The name “shotgun shack” comes from the idea that if you fired a shotgun into the wall of one of these tiny buildings the bullets would go straight through because the building is so small and the walls are so thin.
David Byrne was inspired to write these lyrics by the use of water in African music.
Before the Remain in Light sessions that “Once in a Lifetime” came out of, David Byrne and producer Brian Eno were getting themselves knee-deep in African music, culture, and academia. Byrne was supposedly inspired by his reading of a study on African poetry, African Rhythm and African Sensibility, by John Miller Chernoff.
When people talk about cars from the 1970s and 1980s, they don't normally think of large automobiles; the trend was really towards muscle cars in those days.
With the oil shocks of the 1970s, muscle cars started getting leaner and consuming less fuel. SUVs and the other "large automobiles" that we think of today did not become popular until the 1990s when the economy was very strong under President Bill Clinton.
This line seems to say that these moments where we freeze and realize all the success we've had are perhaps counterproductive—money lost.
That this mindset of the ultra-productive (some say greedy) young white professional, or yuppie, is what the song is about is not contested. But is the portrayal positive? Does the song criticize the blind materialism of these yuppies, or does it celebrate the upper middle class achievements of these professionals? Critics generally interpret the song as a tongue-in-cheek criticism, but lyricist David Byrne and producer Brian Eno have maintained that the song is plainly optimistic about the wonderful world we live in. The recessions in 1982 and 1987 would leave the yuppies asking, “Where has the money gone?” but “Once in a Lifetime” was released in 1980, prior to those events.
David Byrne's use of water imagery in the song was inspired by his reading of African poetry.
The importance of water in African culture cannot be overstated. In much of Africa, water is extremely scarce, so the rivers and oases that do exist are highly revered. Sometimes this takes the form of religious reverence: Osiris was the Egyptian god of life and death, and he controlled the floodwaters of the Nile; Mami Wata is a current water deity that believers hold as a seductive woman that can abduct you when you swim, but if she decides to let you live, she leaves you better looking, at ease, and more successful. Authors like Patrick Chamoiseau have helped Mami Wata remain relevant. Some also speculate that river meetings between friends and tribes created the modern call-and-response rhetorical form in black churches because people would have to holler at each other from different sides of the river.
And while we’re on the subject, here’s a fun fact: there's about 350 billion cubic miles of water in the oceans. There are even these things called submarine rivers at the bottom of the ocean. They are deep-water ocean currents that cycle ocean water across the entire world.