Speed-solving meant that “Pal of Chewbacca” got misidentified as a four-letter answer, and “Dadaism pioneer” fooled me in a way that’s common when I don’t see an indication like the (3,3) that we have in our crosswords — I was looking for a six-letter artist surname.
E.M.T. was one of those U.S. abbreviations that are a bit dangerous to guess at, so I left it for later, and I didn’t have enough checkers (crossers) yet for CLEAR to describe itself. MAE Jemison was unknown but very likely from _AE.
GRUMPY CAT was easily recognized, but still not noticed as theme content. HAL, like the later CABARET, was a film answer suiting my age. I didn’t know that “haste makes waste,” but could see that the more familiar “more haste, less speed” was not helping. The “soon-to-be graduate” worried me a bit, as U.S. college jargon isn’t a strong suit (fraternity and team names especially), but I knew about SENIORs.
AAH rather than AHH was my next wrong punt, and the slowest to sort out, as I didn’t know exactly what Buzzfeed was, or that MASHABLE was an alternative. Around this time, I must also have put in the other one, STOATS rather than SABLES, “helpfully” remembering that ermine can mean a stoat in its white winter fur. That in turn made AHAB embarrassingly difficult for someone who should have known it instantly, but RAGING BULL fixed it, still without triggering any theme thoughts.
The remaining Acrosses were easy, with TINA and TEDS having enough checkers for my ignorance not to matter. Most of the unsolved Downs fell as I worked my way through them, with MASHABLE and TOUCANS as the main “didn’t knows.”
At last, theme enlightenment revealed that I needed a “displeased critter=____ LADYBUG” pair for 23A/51A, with _R_UCHY having to be GROUCHY and MAN RAY emerging along with GMC.
Overall assessment, apart from thanking Deb for picking an easy one, is that this seemed a very accessible puzzle, with a well-executed theme.