Sorry, perhaps not universal! I knew several dog-owners who would call their pets 'Sir' when they misbehaved. I actually think Patrick's line is pretty funny--it's 'answer to Sir' that does it (and hence reminds me of the dog-owners)--but funny because of its careless arrogance: that slight sense that Patrick's used to seeing everyone around him in the character of employee (see also 'our old lad' for the priest, perhaps?)