End-of-novel blues

I usually get stuck at least once somewhere in the middle, but the very hardest part of a novel for me is the end. I'm trying to figure out why. I already know what's going to happen. I'm hitting the home stretch, and you'd think I'd find some momentum from what I already wrote to carry me through to the finish line.
Nope. So why is it so hard? Is it because I already know what's going to happen, so it's boring to actually write it? Is it because I know what has to happen so I'm afraid it won't work? Is it because I'm so close to being done that my mind is already at the finish line and my fingers don't want to exert the extra little bit of effort it takes to get me there?
No, I think it's because I know this is where I either fail or succeed. Either it works or it doesn't, and this is where I find out. Oh, sure, I'll revise, but the big undertakings are most daunting at two phases: just before you begin and just before you end. Even if you're not writing, any big adventure has its scary moments where all the demons in your head tell you you're going to fall flat on your face. And for me, they shout awfully loud when I get near the end. It seems too hard, the whole novel seems too ridiculous, and the prospect of revising it and getting it published is just as scary and laborious as writing a first draft. So abandoning it (and starting on my third novel) seems much easier than finishing what I've got. Of course it's not--I want to be able to remember what happens to my characters before I abandon them. I don't know if it gets any easier when you have an agent or editor cracking the whip behind you, but I'll tell you this--it sure is easy to procrastinate those final scenes in the final chapter when you've only got yourself to answer to. And the blogosphere. Whoops. Maybe I'll get back to work this week.