I used to go at 6AM on Sundays to avoid all that, but I kind of fell out of that habit. I probably need to start it up again.
The funniest/worst, was being trapped in a line at the checkout, behind a very old couple. The cashier asked if the woman had a shopper's card, and the woman dumped the entire contents of her massive purse onto the conveyor and pulled out card after card:
"Is this it?"
"No, ma'am, that's a credit card."
"Is this it?"
"No, that's your driver's license."
"How about this, is this it?"
"No, that's a pack of gum."
On and on this went, until she finally decided to just open up a new one, so that took a few minutes, then they finally got her groceries scanned through, then it was a whole thing counting the cash to pay for it.
Finally, all done, she starts to wheel away her cart, and her damn husband pulled a candy wrapper out of his pocket and said, "Oh yeah, I forgot to tell you, I ate this earlier." - and the way he said it and giggled, I just knew he didn't forget at all, he did it on purpose.
And of course, that started the whole thing over again, including looking for the shopper's card she just got and had already misplaced.
You are reminding me of one of the many reasons I do most food shopping on-line.