Jeez...It may be January but ranting about someone wishing you a nice day?! I can't believe so many forum members feel so strongly about it. I feel angry, depressed and losing hope for humanity reading this thread!
It's the done thing to wish someone a nice day while you're manning a checkout. Granted, I suspect not many of you have done so on a regular basis. However, most of us do *try* to inject some personality into the conversation, especially the more old-school of us. Even just mixing it up with "have a good afternoon/rest of your morning/evening", "take care" or similar is better than nothing. However, I'm expecting to hear soon why all that is wrong too!
You have to realise we don't just say these things for fun, it is common company policy to do so. Quite frankly, most of us would be happy to just whizz everything through, take payment and see you leave. Especially miserable people, jeez that can be soul destroying dealing with such hateful people that you can come across.
The quicker we convert all checkouts in supermarkets to self-scan lanes the better in my eyes. It's so much more efficient that it should happen as soon as possible. It won't happen for a couple of generations I suspect though.