In The Destiny of a Few, no character was harder to write than James. I mean he did things like this and until I started editing, I had no idea why:
“So, Mom, do you think Winter is going to make it,” James sounded cold, almost cruel to Maria’s ears.
She turned her head slightly so that she could look up into Letty’s eyes. Had Winter taken a turn for the worse? She thought that Letty had said that she was going to live. Had she only been protecting her? She closed her eyes, as if that would block bad news from reaching her ears.
“James, you know very well that she is going to make it. In fact, Maria, she wants to see you as soon as you are up to it.” Letty slathered cool cream onto the wounded area.
“What about her leg? Do you know yet if she is going to be able to use her leg and walk?” Maria asked.
“Humph, like you would care about that,” James said sharply.
To understand characters like James, you have to dig deeper. You have to find what causes them to do what they do. Is it because they are bitter? Is it because they don’t trust new people? Whatever the cause is, find it out.
The next time a character is giving you a hard time, ask yourself what is the root cause of his/her actions. Answering that will most likely solve most of your issues.