Remember that a manuscript is the result of a writer’s blood, sweat, and tears. Unless they’re lucky to be full-time writers, authors are usually people working a nine-to-five job and have to write during their lunch breaks or stay up late into the night writing after their children have gone to bed. They’ve sacrificed their energy, time, and social life to write a book, and if a query is not handled well, they could see it as an attack on them and not as constructive feedback.