I think it's especially important for an editor to say what he's enjoying. For a novelist to be told, midstream, what he's doing right can actually influence the unwritten parts of a novel in a positive way - praise helps a writer know what's good about what he's written, what's interesting and exciting, and what to work for in writing the conclusion.
Donna TarttNot quite what one expected, but once it happened one realized it couldn't be any other way.
Donna TarttEvery new eventโeverything I did for the rest of my lifeโwould only separate us more and more: days she was no longer a part of, an ever-growing distance between us. Every single day for the rest of my life, she would only be further away.
Donna Tartt