"Long Train Running" (The Doobie Brothers)

A biker band from Northern California might seem like an unlikely place to find the funk, but that's exactly where "Long Train Running" came from.
The Doobie Brothers' singer/guitarist Tom Johnston had come up with the signature riff for "Long Train Running" years before the band actually committed it to tape.  In fact, the song began its life as an instrumental jam that the band would use to fill time at its early concerts, circa 1970.  Johnston never regarded it as a potential hit; it was just a funky throwaway that got bar patrons on their feet and dancing.
That is, until the band's famed producer, Ted Templeman, heard the tune and encouraged Johnston to give it more structure and some words.  Then, it suddenly took on new life as the lead single from 1973's The Captain and Me.
As far as the song's bluesy tale about "Miss Lucy down by the tracks" goes, the story was something out of Johnston's imagination.
"The words were written at the absolute last minute," Johnston told Ultimate Classic Rock in 2012.  "I wrote them in the bathroom at Amigo Studios.  [Ted Templeman] said, 'Write something about a train.'  I said, 'OK! That's a great idea' (laughs)."

Even though The Doobie Brothers had a slew of other hit songs, "Long Train Running" stands out in my mind as the perfect embodiment of the band's sound.  Acoustic yet electric.  Down home yet lowdown.  Rustic yet urban.  It's that unique combination of Johnston's R&B-fueled rhythm guitar against the folksy fingerpicking style of co-lead guitarist Patrick Simmons, underpinned by Tiran Porter's bouncy bass, that created the band's groove in its heyday.  

In any case, "Long Train Running" was a favorite of mine at age 3, and it remains a favorite today.

"Black Water" (The Doobie Brothers)

"Black Water" from the 1974 album What Were Once Vices Are Now Habits was written by The Doobie Brothers' lead guitarist Patrick Simmons.  It was his very first single for the band and, incidentally, the band's first #1 song.  And it came about by accident.
"Black Water" originally was released without fanfare as the B-side of the single "Another Park, Another Sunday," which is itself a great, soulful ballad about lost love by band founder Tom Johnston.  Thing was, "Another Park..." contains the lyric My car is empty and the radio just seems to bring me down, which didn't sit too well with radio programming directors at the time.  So they had DJs flip the single, and "Black Water" took off instead, leaving Johnston's A-side in the dust.
In a 2012 interview with Vintage Guitar magazine, Simmons recounted how he had been working on the song's riff–"kind of a lazy delta blues thing," in his words–just before the band played its first shows in New Orleans.  After soaking in the Crescent City, Simmons said the pieces of the song easily fell into place.
"I think it was all the wonderful experiences–the food, walking along the Mississippi, the French Quarter, Dixieland music in the clubs."
He also recalls how a simple trip to the laundromat resulted in one of the verses of the song.
"I wrote the second verse while riding a streetcar up St. Charles [Avenue] to the Garden District to do my laundry. It was raining–one of those summer showers where it’s sunny. It was a magical moment for me. So I jotted down the lyrics. If it rains, I don't care. Don't make no difference to me. Just take that streetcar that's goin' Uptown."
I think that line and the little tag at the end of the chorus And I ain't got no worries 'cause I ain't in no hurry at all are kind of the essence of the whole song.  (Side note: Hearing that lyric always brings to mind a scene in Jack Kerouac's On the Road, where Dean Moriarty, Sal Paradise, and Marylou are cruising into New Orleans at sunset, grooving to a radio show that's blasting bop jazz and funky R&B, and the DJ keeps saying, "Don't worry about nothing.")
Having been to New Orleans several times, I would be lying if I said the city is all Twainian paddlewheel boats and "funky Dixieland" jazz.  It's not–not for the past century, anyway. (Unless, that is, it's being artificially reenacted in the Quarter for the benefit of wealthy European tourists).  
Nevertheless, Simmons does capture certain qualities of the city that ring true: that living time capsule feel you get riding a century-old streetcar through the Garden District, and that live-and-let-live, no worries/no hurries vibe.  New Orleans is the kind of place where you step inside some shady watering hole just to get out of the heat for a moment, only to find yourself sidled up to a 200-year-old bar, sipping some bright green concoction over sugar cubes that's rumored to cause brain damage, buying rounds of Sazeracs for people who were strangers a mere 60 minutes before, and then suddenly realizing it's 1 am but not really caring that you and midnight never rubbed shoulders, because, God willing and the levees hold, there's always tomorrow.
That's what I hear when I listen to this song.  
That, and I hear a track that defies easy categorization.  (Is it Cajun R&B?  That straight-outta-the-bayou fiddle might make one think so.  Is it funk-grass?  That acoustic finger-picking against Tiran Porter's fat bass would help it qualify.  Swamp rock?  Maybe–but then where does that Southern Gospel harmony/a cappella breakdown fit into the picture?)
Whatever it is, I keep revisiting it.  New Orleans, too.