Imagine a job where you countless hours on a project for months or even years without knowing whether what you are doing will ever mean something in the end. You spend thousands of hours working on something and that might never provide anything in return, monetary or otherwise.
That is what writing a novel is like.
Torture. Are my characters doing the right thing? Is there too much description? How do I use a SEMICOLON? Did I use the word torture too many times? How does it feel to have broken ribs so I can describe it just right? What do horses smell like? Why did he (the character) just say that?
But yet, you have to keep going. You think of one amazing line and that keeps you going, even though the last thousand lines where terrible. Just like when you read a book you want to make sure these characters find happiness and triumph over evil, even though you created them and their situation. You want them to be happy, and hope everything will end well for them. I have spent a million hours with my characters: have wept with them and laughed with them. And yes I fully realize that makes me sound insane.
But somehow happiness in fiction, even if we created that fiction, gives us hope for happiness in the real world.