Nelson's 1971 Yesterday's Wine album is rife with bittersweet nostalgia, from the reminiscing-over-a-bottle title track to the heartbreaking "Summer of Roses." But it's "December Day" that paints the starkest picture of a man taking stock of his year — and a relationship. The artist, still evolving into the long-haired troubadour he'd become, sings of "a time to remember day" and "a spring, such a sweet tender thing" like a country music Sinatra. "December Day" is Nelson's "It Was a Very Good Year," full of poignancy and tinges of regret. It also defines the Christmas month as the saddest of all, something Haggard realized two years later with "If We Make It Through December."