Reflections from the jury pool

So. I didn't picked for jury. Not really a surprise--we had to name our occupation, as well as our spouse's; and with both of us at the newspaper I was probably a definite nix right away. Also, we are friends with the public defender and his wife (the public defender being in the courtroom today), and I knew some of the witnesses likely to be called. All probable strikes.
Also had a little ethical dilemma going on: The defendant sat at the table with our friend, his attorney. As the judge read the charges, I found my heart racing and some VERY unkind thoughts churning. Though not an exact parallel, I had once been in a "situation" with a person who mirrored this person's actions. Clearly my "issues," as they say in the therapeutic world, came up with this. The D.A. had said if we had something come up that needed said in private, we could approach the bench. I did, and said I couldn't be objective. In the event I didn't say anything, I could have been seated on the jury. (Though unlikely, given our occupations and connections.) If I had been on the jury, could I have been fair? I made the decision to be forthright because I didn't think I could be fair. I had already decided this person's guilt.
What would you have done?