We have a guy in our office who constantly takes the piss out of customers on the phone, but does it expertly and subtlely so that they don't realise. Earlier this week we had a customer on the phone called Mr Seaman. Good ol Ray picks up the phone, chats to him for a few mins, but I counted three "ahoy there" and 1 "me old hearty" in the conversation

Customer never picked up on it