I mentioned this in a Tip of the Day a while ago, but it gets my goat every time I go to the grocery store.
You have to bag your own groceries here. I'm actually fine with that. I tended to bag my own in Ann Arbor anyway if there wasn't a bagger already there and the cashier was busy. The problem is that since all the cashier has to do is whiz the items through the scanner, she's done with you faster than you can say "Dank u," and she's ready for the next customer.
In the meantime, you still have a basket-worth or even a cart-worth of groceries to be packed and a line of busy customers waiting for you to get out of the way so that they can be rung up. If you're shopping alone without a buddy to bag, the best you can do is throw everything back into your basket or cart and trundle it to the table at the front of the store to pack into your own bags or boxes.
At least in the States, everyone in line is expecting it to take a little longer and you don't feel so rushed.