Book Characters

I am generally inspired to write a story because I imagine a character first. Every good story starts with a good character. It does not need to be the main character. In fact, many of my favorite book characters are those that play a key role in the story but do not claim center stage. Gollum, Dr. Watson, and Reepicheep are fabulous examples.
(And I must admit that having an excellent villian is very important. I really like when the villians are, well... incredibly villanous!)
A great character takes you into their mind, their thoughts, and their life and leave you knowing sufficient information to love them (or hate them) but still keep you guessing about what they will do next, long after the last page of their story has been turned.
What would the story Hamlet be like if Shakespeare had made Hamlet solemn and timid, not passionate?
Would Miss Havisham still be so captivating and crazy if she had taken off that wedding dress on the day her fiance left her? Charles Dickens knew that Great Expectations needed Miss Havisham and her eccentricities.
Personally, Voldemort would be a little less scary if he did not have red glowing eyes, a forked tongue, and serpent nostrils! J. K. Rowling knew that her books needed an enemy that roused both Harry and the readers to action!
I love discovering book characters that capture my attention. What is my favorite one, you might ask? I have no idea! But I think that is a great problem to have.