I love happy endings. Life is too miserable as it is to read about other people being just as miserable. So, my stories have always had happy endings and always will have happy endings. And I will not read books with unhappy endings. (The only exception to this is Les Miserables. An oxymoron, I know, since the very tittle is miserable.)
...Though, there will be some not so happy times in the middle of my tales. But what kind of story doesn't have some kind of unhappiness involved?