I was called for jury service some years ago. I didn't want to play – it would have been inconvenient, I would probably have dozed off, as I used to in lectures, and free time in retirement is in terribly short supply. I discussed the possibility of getting excused with a friend, an ex-clerk of the court. His opinion was that I had no hope. Naturally, that became a challenge!
I wrote to excuse myself, stating that I thought the adversarial legal system was a poor way to establish the facts of a case, that evidence presented would likely be incomplete, but that the court had no way of knowing what had been witheld, that the legal profession did not have training in logic, and that it seemed to me that, in the courtroom, the ability of the counsel to win the case may have more to do with ability as an orator than as a logician. I therefore thought it most unlikely that I would be able to vote 'guilty' beyond all reasonable doubt, and thus my strong bias towards an 'innocent' verdict made me entirely unsuitable as a juror.
I was duly excused and haven't been called again.