I don't consciously do anything to maintain a unique voice.

Reading a novel in which all characters illustrate patience, hard work, chastity, and delayed gratification could be a pretty dull experience.

The characters you refer to as predatory and unsavory are useful. They're the ones who make a novel into a thriller. They're active, and most of the common virtues, the signs of a good person, are not.

What I look for in any character, good or bad, is whether I can hear him speak. If I can imagine him that clearly, then I can write about him.

Once you have invented a character with three dimensions and a voice, you begin to realize that some of the things you'd like him to do to further your plot are things that such a person wouldn't, or couldn't, do.

I do have to earn a living, so I'm conscious of probable reactions from readers, but the most important one is still the awareness that if I'm not enjoying a story, the reader won't either.

I don't think the problem is that people don't read enough mystery books, but that people don't read.