[6months]

It sounds like you had a great trip!
When I first got started, I noticed the cashiers would sometimes totally bungle my order when I handed them a big stack of coupons. I actually asked on here what people did in the register line. I don't like holding up the line, but, after a while, you get a thicker skin.

I hand my coupons to the cashier one at a time. I do this because I started noticing after I got home that a coupon or two would not have been rang up. I was handing over the stack, the cashier was making a big mess of it all, i.e. Coupons everywhere, falling off the counter, getting mixed in with the ones already scanned, the register would freeze because she was trying to scan the same one twice etc etc etc. So I started handing them over one at a time and every shopping trip goes without a hitch now and we move a lot faster with this method because we are doing a sort of production line coupon scanning. I don't want to be the person they dread to see coming.
I suggest that you find a cashier that you like and train her yourself in how to handle your order.