"Working Man Blues" is about as obviously aimed as you can get, at the core audience of his fans, being blue-collar workers. Even at that, Haggard poses for the cover of the single in full business suit, tie, watch, and all. It's sort of a cool solidarity with the audience, and a sympathetic bit of self-deprecating humor - "Don't I look ridiculous like this?" The suit even seems to be tailored in a just-this-side-of-dandy fashion, just to make the point.
"Working Man Blues" is an excellent example of the country music sub-genre known as the "Bakersfield Sound." Bakersfield, California was the locus of a back-to-basics breed of Country music in the '60s and '70s, popularized by Merle Haggard, Buck Owens and the Buckaroos. It was kind of a "punking" of Country music, removing the slick studio production to focus on the bare essentials.
You can't believe it thanks to the urban sprawl and metropolitan development today, but Bakersfield was once just as rural as the name suggests. As recently as 1970, it was just ranches and farms, from the freeway to the horizon, with a few "wide places in the road" for buildings. Today it's the same smoggy concrete jungle that the rest of California is.
Haggard had an amazing work ethic, firing off an average of three albums in the space of a year. Critics noted that the prolific pace didn't hurt the quality; music critic Mark Deming noted that a performer would be lucky to have the hits spanning a career that Haggard could pack into one album.