Watching my imagination come to life. I love how you learn more about each individual character as the story progresses and they end up developing a life of their own so to speak.
I find that when I write it's not me taking the story on the journey, but the story taking me on the journey. I fall in love with both the good and bad points of my characters.
I have to say that my favourite character in Seductive Truths is William. He essentially is the villain that readers come to despise, but in truth, he is the foundation in what kicked off the story in the first place. Everything else developed around him. And I have Colin Firth to thank for my creation of William as he said in an interview once, "Rather than just playing a psychopath or mass murderer, it was interesting to play someone who is apparently what you expect me to be, [an English gentleman] and then take off the mask to reveal something darker."