I check myself out at Walmart (and anywhere else I can) and then I load my own groceries and yes, I quite often talk to myself while I do it. Most of those conversations are the most fascinating of the day!

If you're shopping at Walmart, then you're no different than the people loading your car. Stop being a snob.

I don’t let store employees pack my groceries into bags or take them out with me.

OMG. OP, they're people like you, not some alien species.

You say, hi, how are you or how is your day going and thank you.

I usually don't say anything when they're loading the groceries in the back of my car. Feels kind of awkward but I don't know what to say.