You know, the people I read for trust me as the reader to do the reading and, like someone else said, their attention is focused on me and what I'm seeing rather than on the cards usually. I also don't read "this card means this and this card means that and that one means thusly", if you know what I mean. In other words, in the Your Readings forum and such here on AT, it's a learning venue so I often do interpret cards one by one and then weave it together, but if I were reading for you in person, I'd be just weaving together what the cards say to me for the reading as a whole, I'm not pointing and saying, "This card is the Ace of Wands and means---yada yada---and this next one is the Emperor and means ---yada yada---" and so on like that. Not any more than I'd interpret each word of a sentence in reading you a story. I'm reading to you what the cards are telling me as a whole in response to your question and they don't always mean what the book says they mean individually. That's not truly doing an actual reading, in my opinion.
So I don't find having the querent sitting next to me is my preferred way. If I were teaching a friend card meanings, then I'd do it card by card.