The point is that these people who populate my consciousness become very real to me. It's the knowing that I have invented them that keeps me what we consider sane. Because I confess that I've been known to fall in love with some of them, grieve for them, lose sleep over them, and hurry to get back to them each morning when I start work again. And always, when I finish a book, I am bereft. I miss my characters intensely, which is why I begin another book as soon as I can.
Plots are essential.
If you're writing a historical novel, facts are essential. But characters are what make or break a work of fiction, and they must always come first. But they continually surprise me as well. If they didn't, they'd only be characters. I want people in my books.