Mari is correct - I had already decided that the person was guilty. That excludes me from the jury automatically based on the rules. I would have gone in presuming he was guilty, and need to see proof of his innocence. I wasn't alone in my feeling. I spoke with several other jurors who dismissed themselves later on in the question process, one of whom was a former coworker. He said that the more they talked about the case in vague terms, the more convinced he became that the guy was guilty.
Positive or negative, depends on what the goal is. If the goal is justice, potentially positive. If it's innocent until proven guilty (which doesn't always mean justice), then negative.