I'll make no bones about it: today's theme is an interesting one. The theme answers are like a DIYKIT for spinal column construction, starting with a single vertebra [I] at the end of MOTHERMAYI, then tacking on a [P] in LIFEOFPI, and building on up through HAIR[PIN] and BACK[SPIN], resulting finally (I'll disclose) in a full-grown SPINE, standing at the back of the revealer: GROWASPINE. I thought it was very neat to start in the middle with [I] and then alternate the added letters left and right. HAIRPIN reminds me of the movie Desk Set. I should watch that again.
There were some crack answers like MOTIF, LAUGHLINE, BALSA, and everyone's favorite, HASASIP. I also enjoyed "Person who really digs working?" (MINER) and "Everybody's opposite" (NOONE). "POD Save America" is an amusing title for a political show. And the combo of COMBOS ("Jazz ensembles") and BRIO ("Liveliness in music") played well together. LATERGRAM was a new word for me, but not a new action ("Photo posted days or weeks after it was taken on social media"). The clue is an apt description of my MO. Apt!
There were a few creaky old bones, too, in particular "Ferry or wherry" (BOAT) and "Turnkey" (JAILER), not to mention "Kate & ____ (1980s sitcom)" (ALLIE). And speaking of the past, I was surprised to see the term ERA applied to "Obama ___ (2009-2017)". Too soon?
I totally misparsed the answer to "Deep down inside". I kept thinking what do they mean 'at the art' (ATHEART)? Also, I don't know whether to laugh or cry at the "doctor-speak" term PEDS for children's medicine. Discuss.