When I read "1A: Welcoming words" I dropped in "please do come in," and for "15A: 'You're misquoting me,'" I tried "I did not say that." Then I immediately went to the Downs, and realized "1D: Home of many Physics Nobelists, for short" should probably be MIT, so 1A came out. SARDINE (8D: Fish typically preserved in oil) quickly followed, ruining 15A, and for a while after that it did not look good for ol' Horace. But slowly, things came back into focus.
1A: Welcoming words (MICASAESSUCASA) - A. Pretty nice. I was going to ding it for being foreign, but it's Friday, so all's fair.
Favorite: MACE (Old ball and chain?) - Even with the question mark, it took me a while, and I laughed when I finally got it.
Least: ARC (Part of a cardoid figure) - I was not familiar with these, and when I looked them up, they were all blobs. And sure, an arc is a part of a circle, but that's weak.
Lots of nice words again today - ATELIER (14D: Workshop), CHEEK (27A: Impudence) (This was a front-runner for "favorite"), ESCAPADE (28A: Wild adventure), and my favorite dessert - TAPIOCA. Mmm.... TAPIOCA....
I liked the fun words, and I like much of the cluing. ROMPS felt a tiny bit off for "Humiliating defeats" (I would have preferred "ROutS"), but I can accept it. On the other hand, "Nice thanks" for MERCI had me fooled for a good long time. Strong 14-stacks, and good content without too much filler. Very nice Friday, Mr. Steinberg.