First chapters are tricky. So are first pages. Writing the first page of a novel can feel like those first awkward five minutes on a blind date, when you're trying to both surreptitiously examine the person you've come to meet and exude some level of confidence in yourself as well.
First pages usually carry a heavy amount of exposition, since this brand new story with new characters is suddenly coming to life out of the ether, and slipping in a bunch of information without it feeling heavy handed is difficult enough. But if a novel is hoping to invoke a dream-like state, as most attempt to do, the first few pages are critical in helping the reader slip away from reality into the fictional world, and a writer needs to do much more than carry a little heavy exposition water across into chapter two. The plot needs to start rolling (the sooner the better), a tone needs to be set that will resonate throughout the remainder of the book, and, above all else, the reader needs to be intrigued enough to keep turning pages.
I can't really harp on this last point enough. I think it's a common mistake for authors, from young to old, to believe that any old crap they find interesting will also be interesting to their readers. They think they can pluck of few discordant things out of the air, like brain surgery and horse racing and collecting gumballs, and throw them all together into this fictional stew, formulating a plot and some characters to go along with the plot, and that because they have a plot they can sort of amble along and survey the discordant things that interest them, say have their characters win at the track and collect gumballs. What I mean is, they don't build their story out of an urge to tell a story, but as a means to research a few topics, build up the old page count, and finally throw a shiny literary veneer over the whole mess, a veneer that's so shiny critics are dazzled by it and mistake it for "art" and "brilliance".
Whoa, I veered offtrack in that last paragraph, didn't I? Sorry. What I mean to say is that first chapters need to do a lot of things at once, and that I've found over the books I've worked on is that your rough draft of that first chapter is often the roughest of the rough because you're still struggling to determine both the novel's tone and who exactly you're writing about here. Your characters are still foggy to you, the plot with its far-reaching implications is probably unclear, and you're sort of lashing out into the darkness with each sentence, hoping to strike gold. More than once I've gone back at the end of a novel's rough draft and rewritten nearly the entire first chapter from scratch, or at least done some heavy duty rewriting. And, sweet fancy Moses, I've had to do pretty much the same thing to entire books, too. I guess the best a writer can hope for is to understand the story they're trying to tell as soon a possible, and hope this understanding leads to lighter rewrites in the future.
Finally, if you'll forgive me a Matrix reference: the first chapter of a book needs be like the red pill, taking your reader down the rabbit hole, because who wants to wake up back in their old life?