Why did Suzanne Collins write Catching Fire?

Answer 1

My assumption is that she wrote Catching Fire because the story wasn't finished yet. There were many unanswered questions that left people pondering, like:

• Does Katniss really love Peeta?
• Is there going to be another Hunger Games?
• Is Katniss going to realize that she loves Peeta and confront him about it?
• Is there going to be a war between the Capitol and the districts? Will people survive if there is a war?
• Will Gale finally work up the courage to tell Katniss that he loves her?
• What will happen after The Hunger Games? Will Katniss live in peace with her family, or will she have to pay for what she did with the berries?
• Is President Snow going to kill her? Or will he find a more suitable way to kill her, not by his own hands but with an innocent person's? Will he put her back in the Games so that she can get killed by a tribute and so that everyone can see her die?

All of these questions and more are going to be answered in Catching Fire and Mockingjay.