How important are those first sentences to you? As a reader? As a writer? Those first paragraphs? Those first chapters?
For me, the genre has a lot to do with the impact of a first sentence, paragraph, and chapter. I've said before, and I mean it, I'm a patient reader. I'm willing to give an author some elbow room in developing a story. I'm also a realist. If I'm not interested or my curiosity isn't piqued by the end of the first chapter or first three chapters if they're short, it might not look good for the book I'm reading.
If I've been given the opportunity to review the novel, and I selected it, I'm going to trudge through the thing regardless of my lack of interest. If I have no obligation to the book, chances are, at this time in my life, I know by then whether or not it warrants any more of my attention.
"First" sentences don't need to be acutely dynamic for me to continue. I can tell you who writes dynamite first sentences, but they're all in the suspense/thriller categories, so they want to grab the reader and shake them if possible. These authors accomplish their goals: Robert Liparulo, Steven James, James Scott Bell, Athol Dickson, and Sibella Giorello. Certainly not the only ones, but definitely good at opening stories.
How do you rate your first sentences in the novel(s) you've written? And how important is it for you to get it just right?
Father, just help me to write the way you want it, to tell the stories you have for me to tell. In the Name of Jesus, Amen.