The Emotion Thesaurus was my main resource during the writing process.
This book gives descriptions and specific thought processes, physical reactions, and possible end results of basically every human emotion.
For example, here is the page on Agitation. As you can see for writing a story this is an invaluable resource
Conflicted was actually an emotion I often referred to for reference. One of the main places this emotion is used is when Charles goes to someone he once loved's house for dinner. He wants them to be happy, but at the same time he doesn't know how to express the mixture of jealously and heartbreak he feels. This conflicted feeling is something that drives him to do something important to the plot later on in the story.
The Thesaurus allowed me to describe this feeling in his body language and not just his inner thoughts of "I'm jealous," or "I wanted to leave."
Without this book as a resource, I know for certain my writing would not be as good as it is. Emotions are a complicated thing, and over-describing/under-describing is something I struggle with. If anyone is looking for even a more in depth analysis of human behavior, I strongly recommend you pick this one up.