Need's a funny fish; it makes people untruthful. They all suffer from it, but they won't always admit. — Salman Rushdie

Happy ending must come at the end of something. If they happen in the middle of the story or adventure, or the like, all they do is cheer things up for a while.

Now the Tale of the Moody Land was one of Rashid Khalifa's best-loved stories. It was the story of a magical country that changed constantly, according to the moods of its inhabitants. In the Moody Land, the sun would shine all night if there were enough joyful people around, and it would go on shining until the endless sunshine got on their nerves; then an irritable night would fall, a night full of mutterings and discontent, in which the air felt too thick to breathe. And when people got angry the ground would shake; and when people were muddled or uncertain about things the Moody Land got confused as well - the outlines of its buildings and lamp-posts and motor-cars got smudgy, like paintings whose colours had run, and at such times it could be difficult to make out where one thing ended and another began... (Salman Rushdie)