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 TarttThe firelight magnified our shadows, glinted off the silver, flickered high upon the walls; its reflection roared orange in the windowpanes as if a city were burning outside. The whoosh of the flames was like a flock of birds, trapped and beating in a whirlwind near the ceiling. And I wouldn't have been at all surprised if the long mahogany banquet table, draped in linen, laden with china and candles and fruit and flowers, had simply vanished into thin air, like a magic casket in a fairy story.
Donna TarttIt is easy to see things in retrospect. But I was ignorant then of everything but my own happiness, and I donโt know what else to say except that life itself seemed very magical in those days: a web of symbol, coincidence, premonition, omen. Everything, somehow, fit together; some sly and benevolent Providence was revealing itself by degrees and I felt myself trembling on the brink of a fabulous discovery, as though any morning it was all going to come togetherโmy future, my past, the whole of my lifeโand I was going to sit up in bed like a thunderbolt and say oh! oh! oh!
Donna Tartt