With a strong interest in psychology combined with a more obvious interest in books, I thought there were some interesting pearls of advice in this piece. It suggests using a well-known psychological concept, "The Five Stages of Grief", to create a character's response to anything they might be going through in a meaningful, believable way. He coins the stages for the purposes of character development "The Five Stages of Misfortune", a clever way of spinning this to apply to fiction. I read so many submissions where I find the characters don't handle their emotional life in a satisfying or realistic way, and it definitely impacts the overall success of a story. Like Jason Black, I'm not convinced that each of these stages of misfortune needs to be followed in every case, since not all misfortunes are created equal and you don't want an overly dramatic reaction to a relatively minor problem, as his example of stubbing a toe illustrates. But I do think it's important to keep reminding yourself as you are writing that all your characters need to be fleshed out in big and small ways depending on what they are going through in their emotional life. Using these guidelines as a reference is a good tool for that.