I have name changed as I work in the criminal justice system and don't want to be recognised from pervious posts.
Jury service does involve a lot of waiting around, being brought into court to be kicked out again and sometimes waiting around to never enter court. It can be frustrating as a juror (I have been one) and the reasons for delays etc are not always explained to a jury which can make it more frustrating.
They call more jurors than needed as some longer trials start with 14 jurors, they need "back ups" if jurors attend and have reasons they cannot sit in trial such as knowing the defendant or witnesses etc or reasons such as childcare preventing them. They may have trials listed that are expected to start but then when crunch time hits the defendant offers a plea. This means a jury isn't needed and the trials on stand by to jump in the gap won't necessarily be able to start that day causing a delay.
There is often legal argument which jury cannot be privy to. This is where the defence or prosecution raise something with the judge. The judge needs to decide on how to proceed before calling them back in. It is unavoidable in many cases as things crop up as witnesses give evidence.
There are many harrowing cases that come into court and I see it time and again where jurors come in eager or annoyed to be there only to be told what the case is about and seeing their faces drop, eyes well up and a bracing themselves for what to come.
It's can be a lot of information especially fraud cases and some of it very complex. You then need to come to an agreement with 11 other adults who have their own minds, opinions and emotion and need to try leave the emotion at the door to deliver justice. It's a huge weight on someone's shoulders to carry. It is interesting but be prepared for it not to be easy. You will never get all the answers you want as a juror and that can be frustrating.
I recommend visiting a court and sitting in a public gallery if you want to see what goes on throughout.