You're Dead to Me. The word Dead can be placed before the first word of each starred answer to give common phrase.
15-Across. * Instant in which emotional decisions are made: HEAT OF THE MOMENT. Dead Heat.
61-Across. * Defeat soundly: BEAT THE PANTS OFF. Dead Beat.
1-Down. * Flaky type: SPACE CADET. Dead Space.
28-Down. * Employment field: LINE OF WORK. Dead Line.
And the unifier:
37-Across. Like jobs with no future ... and what the start of each answer to a starred clue can be?: DEAD END
Across:
1. Shipwreck signal: SOS. // And 55-Down. Palindromic pop group: ABBA.
4. Stan of Marvel Comics: LEE. Stan Lee (né Stanley Martin Leiber; Dec. 28, 1922 ~ Nov. 12, 2018) was the central creative director at Marvel Comics for over 20 years.
7. Catch in a trap: SNARE.
12. Time period: SPAN.
13. Off-roader's purchase, for short: ATV. As in All-Terrain Vehicle. Not to be parsed as A TV.
14. Quest for intel: RECON. Short for Reconniassance.
18. Middle-earth menace: ORC. The fictional characters made famous from the Lord of the Rings, by JRR Tolkien (1892 ~ 1973). These characters, however, had previously appeared in folklore. // And 11-Down: Tolkien tree race: ENTS.
19. Female surfer: WAHINE. Top Female surfers. Bethany Hamilton (b. Feb. 8, 1990) is an American surfer who, at age 13 lost her arm to a shark attack, yet she still went on to become a professional surfer.
20. Times to remember: ERAs. I remember doing laundry over the years. In fact, I still do laundry.
21. Got a lift, in a way: UBERED. I have never used Uber for a drive.
23. Popular mints: CERTS. They are 2 mints in 1!
25. Tea container: CADDY.
27. Gradually come to be: DEVELOP.
31. Wander about: ROAM.
33. Pasture: LEA.
35. Where one may be taken to be reprimanded: ASIDE.
36. Verb in a recipe: ADD.
40. Tennis court divider: NET.
41. Family gathering attendee: NIECE.
43. Pacific Coast st.: ORE.
44. Loch with a legend: NESS. Real or fake?
45. Ties to a post: TETHERS.
48. Rene of "Get Shorty": RUSSO. Rene Marie Russo (b. Feb. 17, 1954) makes frequent guest appearances in the puzzles.
50. Show flexibility: ADAPT.
52. Dampen, as sound: MUFFLE.
55. Help in a bad way?: ABET.
58. Coral named for its shape: SEAFAN. It's so beautiful.
60. Wheaton who played himself on "The Big Bang Theory": WIL. I never watched The Big Bang Theory, nor am I familiar with Wil Wheaton (né Richard William Wheaton, III; b. July 29, 1972). Apparently he is an actor.
64. More despicable: BASER.
65. Talk trash to: DIS.
66. Cork's country: EIRE. Also known as Ireland.
67. Cowboy singer Gene: AUTRY. Gene Audry (né Orvon Grover Audry; Sept. 29, 1907 ~ Oct. 2, 1998) was known as The Singing Cowboy.
68. Uneaten morsel: ORT.
69. Ship in Genesis: ARK.
Down:
2. Cheerios grain: OAT. We seem to always have a box of Cheerios in our cupboard.
3. Came down in flakes: SNOWED.
4. Plastering strip: LATH.
5. Value system: ETHIC.
6. Tied, as a score: EVENED.
7. "Seats all taken" sign: SRO. Standing Room Only.
8. Archrivals: NEMESES.
9. Asian laptop brand: ACER. I learned about these computers from doing the crossword puzzles.
10. Barrett of gossip: RONA. Rona Barrett (née Rona Burstein; b. Oct. 8, 1936) makes occasional appearances in the crossword puzzles.
12. Macedonian neighbor: SERB.
15. MLB's Astros, on scoreboards: HOU. Hi, D-O!
16. "Fiddle-__!": FADDLE.
17. Trifling: MERE.
22. Battering __: RAM.
24. Spot on the tube: TV AD.
26. Vote of support: YEA.
29. Keats works: ODES. Odes have become a crossword staple.
30. Vets' concerns: PETS. Dr. Oakley treats pets and wild animals.
31. Rave's partner: RANT.
32. Dog in the comics: ODIE.
34. Brouhaha: ADO.
37. Owner's document: DEED. Who owns the house?
38. Blunder: ERR.
39. Mad Magazine mascot Alfred E. __: NEUMAN.
42. Idle talk: CHATTER.
44. Bounced-check letters: NSF. As in Not Sufficient Funds.
46. Reckless: RASH. Or, what one gets from walking into poison ivy.
47. Racer's bathing suit: SPEEDO.
51. Animal with a snout: TAPIR. We got a glimpse of a Tapir when we were in the Peruvian Amazon.
54. Santa helper: ELF.
56. Steady guy: BEAU.
57. Toward sunrise: EAST.
59. Speedy: FAST.
62. "Do or do not. There is no __": Yoda: TRY.
63. Title for Paul or Ringo: SIR. Prince William knighted Ringo Starr.
Here's the Grid: