Happy Endings?

I used to think that happy endings were for fairytales and though I certainly preferred one, it was wrong to do so. However, particularly after reading 'Atonement' by Ian McEwan, I have changed my mind. I no longer think books with sad or inconclusive endings are any more profound than those that end happily (there are some exceptions where a happy ending would be all wrong). In 'Atonement' the narrator is a character in the story, but she is writing the events as a novel. At the end there is a section in first person from this narrator about her life outside the novel. She confesses to have given her sister and herself a happier ending in the book than in real life, and so it got me thinking about endings.

When I refer to a 'happy ending' it does not have to be love and marriage and happily ever after lets drive off and win the lottery, I just mean something with some optimism. One of my oldest arguments in favour of such an ending,  is that the author is in control. They are showing us a period of time and can extend or shorten that time to suit themselves, I'm convinced that if they carried on a story for long enough, or less convincingly, ended it earlier, a positive ending is always possible. Even if there is a zombie apocalypse and all life on earth is wiped out, you could fast forward to see new life born on the planet giving hope for a better world.  

Alternatively, just a sentence of optimism could turn around a novel. Perhaps a character reflects fondly on a past event or has an ounce of hope for the future. This could count as a compromise surely! Or maybe just a nod to the 'circle of life' could improve matters.

However, this could be construed as 'cheesy' or not reflecting the true nature of life. It could ruin the tone of a wholly depressing novel which is about a disillusionment with man. This I can understand. 

But what is it I want from an ending, and why do I so much want a happy one? I have read books with underlying melancholy tones and just to peter out with that flatness is, quite frankly, depressing. I read another book in which it flashed forward to the old age of the young women in the book. To see that her life had not improved much, or been what she hoped and that she had little chance in the future to change this, was also depressing (probably more realistic, but shh)! I think what I do want from an ending, even if it is a solidly bleak one, is a satisfying conclusion. Frankenstein, from what I remember, does not have a cheery ending, with the creature becoming bezzies with old Frankenstein and appologising for killing half of Frankie's friends and relations. However, there is some kind of perverse satisfaction to them chasing each other across the globe to the end. It works. And so, happy or sad or just vague, that is what I want, an ending that works.

What do you think? I would be really interested to here other views on this topic :)