Your jury duty experience was different than mine then. I sat on a criminal trial where we were told almost nothing about the numerous past convictions of the defendant, the fact that he beat his girlfriend, or the fact that the trial's key witness had been beaten shortly before the trial began in an apparent effort to prevent her testimony. I learned about all these things only when the trial was over. The judge even threw out a recorded phone call that the defendant placed from prison because it repeated some boilerplate disclaimers about the call being from a prison inmate.
My jury experience led me to believe that evidence rules are very stringently applied.