If you're bright and critical, you will be weeded-out early by prosecutors, and you'll see the type of people the prosecutors want deciding a case.
If you're coy enough to play dumb and get selected, you'll get to see the shallow reasons other jurors choose to declare someone guilty.
I was so personally disturbed by my experience as a juror that I pledged to never accept a jury trial if I was wrongfully indicted; I'd rather take my chances on appeal after letting a judge decide my guilt.