I stopped at the store yesterday after meeting for breakfast with my brothers. My experience closely echoes yours. Lots of grim faces but basically civil.
LONG lines at checkout. The checkout clerk I got was clearly new and a bit shaken. Her training obviously didn’t include onslaughts of surly customers. She greeted me with a “How’s your day?” and I answered “good” and added, “So, how are YOU doing?” We chatted (just a little!) as she rang up and I helped bag groceries. She admitted to being a little overwhelmed and I kinda half-whispered “you’re doing fine”.
This too shall pass...
That was very kind of you and probably appreciated more than you can imagine.