I was so excited when I got jury duty for a drug case - until I had to inform the ADA that I was casually acquainted with the arresting officer! I hadn't recognized his name when filling out the questionnaire, and didn't know whether to keep my mouth shut once he'd testified. Luckily, I did say something, because he'd immediately informed the ADA that he "knew" me.
Talk about an uncomfortable situation. The judge hauled the attorneys and us off to his chambers, and didn't seem to understand how we could have been casually acquainted by first names only because we frequented the same tavern on Friday evenings for 5 or 6 years, and I thought he (the cop) was a musician, I was only 2 years past the legal drinking age at the time, and the tavern in question was owned by a retired cop and his cop brother, who "should have known" that I was underage, as the co-owner who was a cop worked with my then significant other. What a mess!
Luckily, he decided not to pursue the "irregularities", and simply dismissed me as a juror. Never again!