Happiness is an allegory as happiness is always pointing to something else. One does not get to rest in happiness. On the other hand unhappiness makes for a better story because suffering and struggle makes for a good story. If the prince did not have to suffer crossing seven seas, climbing seven mountains, defeating seven monsters to get to the princess, it wouldn't be meaningful story or romance. In fact, one could almost say, blessed are the unhappy for it makes their story more meaningful (Matt 5:4). That is why unhappiness in not (always) a bad things after all.