What draws you in?

There a two major schools of thought on how a book should start. One: Your first page must be snappy, the words gripping with a hook that often has little to do with the story per se (this is the modern post consumer rush school- propounded by editor's and agent/publishers.)

Two: The page should be a seamless transition of writing, not necessarily memorable from sentence by sentence. As in Steinbeck's The Grapes of Wrath : To the red country and part of the gray country of Oklahoma, the last rains came gently, and they did not cut the scarred earth. And Golding's Lord of the Flies : The boy with the fair hair lowered himself down the last few feet of rock and began to pick his way towards the lagoon. Finally Trevor's Three People : On the steps of the Schele's house, stained glass on either side of the brown front door, Sidney shakes the rain from his plastic mackintosh, taking it off to do so.

Beautiful because in Steinbeck, the land is the core of his book, those that work it and those that exploit it. Golding  shows us Ralph, soon to be joined by piggy, that tragic fat boy that so many seem to warm to and despise in equal measure. William Trevor shows us Sidney, a quiet man in love with an older woman with a horrible past. All these are not the modern school of thought's big slap in the face. But they manage a greater impact because a: They are better written and b: They are intregal to the story.
So here is my question (at long last you all cry ): What grips you when you read the first page or two of a book. What calls to you, so that instead of placing that book back into the squeeze of its siblings, you carry it to the counter?
What speaks to you in that moment. Is it the writing? Is it the blurb on the back of the sleeve. Is it because  that was the book you entered to buy in the first place?
What grips you?
For me It is not the first hook line or clumsy attempt to catch my interest, only to find the next ten pages have little to do with the opening. No, it is purely down to whether the paragraphs flow until without realising I find myself at the bottom of the page, knowing I have read a well crafted opening but finding the journey effortless.
By the way I heartily recommend Steinbeck. He is a consummate wordsmith. And my favourite author, by the slimmest enamel of your gnashers. Laters Griff.