THEODICY looks so much like "the idiocy." I think Sam is making subtle commentary about religion, but I'm too much of an idiot to figure out what.

Three fantastic marquee answers, NIGHTY NIGHT, STAIRMASTER, and WORLD ATLAS firing on all cylinders. Not only are these fantastic phrases in their own right, but each is screaming to take a clever clue. The first has all sorts of potential around "retirement," the second was clued just as sneakily a few weeks ago, and WORLD ATLAS has plenty of plays on "country" available. Yes, yes, and yes!
AT THE HEART … not so much. The knock on it is that it wants so desperately to be completed by "of," so you have to include that in the clue. Makes it edge toward partial-land.
Sam debuted a few entries today, but that's not always a good thing. NIGHTY NIGHT, absolutely. TYREKE Evans? I've had on my fantasy team many times, so I know his name. I don't think it's fair to expect non-NBA data crunchers to know him, though.
Along with AT THE HEART, there's RUNS A LAP. I thought about it for a while, deciding not to ding it. It's not as strong to my ear as RUNS LAPS or TAKES A LAP; however, it'll do in a pinch.
CYBERLAW is a thing, but I doubt I'd ever drop the word in conversation, especially not with my neighbors who work at Twitter and Slack. I already had this happen:
"SLAC! Neat, you work at the Stanford Linear Accelerator Center?"
"Uh …" (eye roll emoji tweeted)
I enjoyed many clues, some of which could use some explanation:
- "U and I" have SYMMETRY in common? Yes, mirror SYMMETRY, my favorite type!
- CANNERY is a "bean plant" … d'oh! Not a bean plant plant, but a bean canning plant.
- [Flat part of a flat] had me thinking about musical flats. Then residential apartments. Finally, the SHOE (a flat is a type of shoe) dropped. Hopefully, the cleverness here didn't fall flat with you.
A lot to love in this solve. Some beautiful feature entries, excellent supporting cast, and nothing that stuck out too much. A couple of wrinkles ironed out (THYMES plural, I see you) and it would have gotten some POW! consideration.