To demonstrate the justice is not only blind, but wildly groping to find a light switch, here are my answers. No, but it's not because I couldn't have been. And I've been falsely accused and interrogated accordingly.
But I've also been on the other side, as a foreman of a jury, and I found that as bewildering as anything. We convicted, but felt awful about it until afterwards we received a whisper from a knowledgeable party that the accused had done the same crime before (which was, of course, inadmissible).
My mysteries aren't police procedurals. I think an imagination and narrative flair are both critical to any writing, because even if you "were there," if you can't imagine the unseen, interpolate character dynamics, structure a compelling story, and drive an exciting plot, no amount of "reality" can rescue you.
One of the reasons I don't think much of the jury system. They won't give you enough information. If it is germane for the defense to bring character witnesses to the saintly behavior of the defendant, it should be equally admissible to bring proof of his past criminal behavior.
Having judges decide everything has its problems too though. (FYI, Japan has just switched to the jury system.)
But I share your concerns, I.J. The only time I was ever seated in a jury a man was being sued for the improper installation of a wooden gymnasium floor. During voir dire, i.e., when the lawyers took turns selecting the jurors, a retired man who'd spent 40 years installing gynasium floors--a coincidence of stellar proportions--didn't make the jury, and I, who knows not the first thing concerning any carpentry or construction, made it. (The next day the case was settled out of court.)
What never made sense to me was the glaring conflict of interest in the cases involving the government as a plaintiff or defendant. The government judge and the government attorney get their paychecks from the same employer: the government. How can that situation possibly result in an objective ruling?
Yes, people in government have different points of view. But so do people in business. It would be a conflict of interest if the judge and the ADA both worked part-time at Wal-Mart. Why is it any different when it comes to government employees?
Take for example county courtrooms, where most legal proceedings take place (in the U.S. at least). The judge often works in the same building as the county attorney. They work for the same employer. Why isn't that a legitimate conflict of interest?
Truth really is better than fiction. I've seen and heard things that boggle the mind. People say, "Where do you get ideas?" Sit in a cafe and listen to the conversations around you. Even better, buy a cop a cup of coffee and listen to the tales.