Mollie, the most important duty of a citizen, above all the other worthy things one may do in life, serving on a jury when chosen is the most important.
If you or any of your family were on trial for anything the first thing you would want to know is that the jury chosen to reach a decision on you or your family were a proper representation of all society. If all those who didn't want to do jury service were allowed to withdraw juries would contain only the cranks, crackpots, biased and barrack room lawyers. Would you want a jury like this making decision on the guilt or otherwise of you or your family? Yes, all those turn up on juries now but there are normally a solid majority of people who are a reasonable and rational and keep the oddballs in order.
I am not suggesting jury trials are without defects but they are the best we have and I believe it is everybody's duty to play their part in it to keep it as good as it can be.