What is it about mumbling? Does that really help any particular situation?
A lady drops off a new prescription. The Rx doesn't specify tablets or capsules. I only have capsules in stock. I tell the lady. She asks if the capsules are pink. A discussion on therapeutic equivalence follows. I can tell she's not convinced. Seeing as how it is now three minutes until closing and I want to go home, I tell her she's overthinking it and I'll fill it for what we have and step away to the filling station.
A few minutes later at the register I can barely hear her say, "I don't trust capsules." Based on the fact she was mumbling, I'm not sure if I was supposed to hear it or not. But at this point I don't care. It's past closing time and I've had enough. You interns and first year pharmacists can deal with these people.
I don't know why people mumble. I guess it makes them feel better. But if you're going to mumble in front of me, I'm going to figure you don't want me to hear it and ignore it.