In “Happy Endings,” how is happiness defined, and what does it seem to depend on?

In “Happy Endings,” how is happiness defined, and what does it seem to depend on? By the end of the story, what is the author’s message about happiness and tragedy, and what kinds of lessons can we learn from each (as depicted in the story)? Moreover, what kind of life would you prefer to have (A, B, C, D etc.) and why? Provide specific details from the story to support your answer.