I mentioned last time out that I had more to say on this point than on any of the others, so here's a post dedicated specifically to climaxes.
To start with a complete non-sequitur, I hate sit-coms. I also don't enjoy them, but for a different reason. The reason I don't enjoy them is that I can't help imagining myself being caught in whatever situation the comedy is being drawn from, and most situational comedy (or at least, all of it that I've ever seen) has involved situations that would be a nightmare for me if I found myself in that situation.
The reason I hate them is that most of the sitcoms I'm at all familiar with begin most episodes by giving you two to five minutes of witty exchanges between fundamentally likable, sympathetic characters. They have to do this because it's how sitcoms work - give you a bunch of characters you like, then kick them all in the proverbials for comic effect. The appeal of the characters is what holds the audience's attention.
And that means that my attention gets held. To the point where sometimes I can't look away as the scenario develops. In one or two extreme cases, this has actually left me with the same kind of half-awake nightmare-type experiences I get from horror films (a subject for another time). I've learned to look on all sitcoms as particularly sadistic psychological traps.
What's all this got to do with masturbation? Well, it's a rare sitcom that escapes some sort of masturbation joke, but that's entirely beside the point. I just needed an inuendo to meet quota.
The point is how this relates to writing more generally: if you hook someone, you'd better be delivering them something they want, or they're going to feel manipulated and maybe even cheated. The hook - the beginning of your novel - had thus better match up to the rest of the story. The important bit in terms of a reader's overall response is always going to be what happens after they're hooked.
Think about it this way. A story is what happens when a character changes. In the hook/beginning, you're given the character. Then you get the conflict that's going to force them to change, and then you get the change. The crucial part of a story is the motion up to and including the climax.
Imagine you pick up a book, check the first few pages and get completely hooked - you fall in love with the main character instantly, and they seem to be setting off in an interesting direction. You buy the book, get home and devour the first few chapters. You keep reading, but the direction and drive begin to fizzle out. You love the character, so you press on... until the point, ten pages from the end, where he wakes up to find it was all a dream.
You'd be furious, I'm sure (unless there's a good way of doing 'and then he woke up and it was all a dream' that no-one's found yet, but I doubt it). On the other hand, a book that you try on a recommendation, where you don't really get into it until half-way through, but which gets better and better up into a knock-out finale is always going to leave a good taste in your mouth.
As an example, this was more or less my experience with the first Harry Potter book. I hated the Dursleys, found them repugnant to read about, and felt that they overstayed their welcome by many pages. I didn't get on too well with the early parts of Harry's schooldays, and the odd bits of fish-out-of-water stuff where he didn't really know his way around wizarding culture. But by the end of the book I loved it as much as anyone lucky enough to read it at Harry's age.
I'm not saying that nothing besides a good ending is important for a book. I'm just saying that you can't have a good book without a good ending. Anything else (except, maybe, the relationship between character and plot - again, a subject for another time) can be merely alright, but a strong climax is vital.
Which brings us neatly back to masturbation. I said last time out that one way in which writing is like wanking is that if you want people to pay for you to do it for yourself, you're going to have to put on a good show. People won't pay unless they think you can deliver, and the most important thing they're going to want is the climax.
The trouble is, you can't market your climax. Well, you can, I guess, if you're marketing your masturbation. But if you're marketing your stories, not so much. If you spoil the ending anywhere before the reader's read the book, there's no point them reading it.
It's particularly bad if you're a debut self-publisher. The main promotional things you can control are your cover, your blurb and your sample on Amazon/Smashwords etc. Hopefully you can also get some reviewers to say nice things about your ending, but that's doubly out of your control - first because you can't control the reviewer, and second because you can't control whether any given reader trusts any given review. Your sample and blurb can only give away your beginning, maybe a tiny bit of your middle. No ending.
I was going to go on a lot longer on this point, but it stopped being funny and became a whole separate post about where the value of a book comes from, as against where its price comes from. I'll write that one when I've come up with a decent inuendo (sorry, an indecent inuendo) for it.
In the meantime, think about the puzzle of how to market your climax without giving it away. Because nobody should be climaxing for someone else's benefit for free...