This is sooo annoying! Cashiers chatting back and forth while scanning your items, and in the store where I shop it's 99% of the time in a foreign language.
Not just cashiers, either. I've seen managers and assistant managers actually blocking customers and their carts while they have a conversation about a sports event or goodness knows what. In the aisles it's usually stock clerks gossiping about other store personnel. The worst offenders are the managers, however.
At least get out of the way so we can leave the store after we've made it through the checkout lane!