For true justice in a court of law, those deciding upon the evidence, must weigh that evidence objectively, without unduly favoring one side or the other, and certainly not giving more credence to one party over another, simply because you like one better or dislike one more. Since we are all subjective human beings, it is somewhat of a real challenge, to not let our own prejudices and emotions overcome us when deciding another person's fate. We owe it to the person on trial, though, or the case being litigated, to give proper consideration to all the evidence and most certainly to not jump to a particular conclusion before each side has had its complete say in court. The significant issue with determining in your mind that one side's story is the story before all the evidence is either complete or fully weighed, is that having done so, you will subtly or deliberately begin to take subsequent evidence and weigh it not against truth or fairness, but weigh it instead against whether that evidence confirms your story and thereby validates it, or whether it doesn't and often times thereby ignore or dismiss it.
It certainly is not easy for a judge to properly be fair in a trial, but at least a judge is skilled in the law and has been trained in the ways of it, whereas, the general public, for the most part is not. While judges will instruct the jurors on how to weigh evidence so as to be impartial and also instruct the jurors not to discuss the case with other jurors until such time as all the evidence has been presented, the truth of the matter is that jurors aren't going to follow that instruction all that often or all that well, mainly because jurors want to talk and communicate with each other, and humans being humans, rather than starting with the weather, sports, or entertainment will move right on to the case itself, as a valid substitute, since that is the relevant item of the day.
The thing is that not only will jurors want to talk about the case, but also the jurors talking to each other, will already have taken a look at one another, and in one way or another, in one form or another, decided that the jurors that they feel that they have more in common with, whether that be by sex, age, race, perceived religion, or perceived status, will almost invariably lead to little cliques forming that will then test each other out, so as to determine as to whether they are seeing things the same way, thereby receiving validation on their theory, or not, and so on. All of this, unfortunately, trumps over the evidence, because ultimately most people placed into public areas and the testing of character, want to, for whatever reason, valid or not, to conform to the prevailing view of their respective group.
One way, perhaps, to overcome this bias upon juror deliberations, is to request from each juror before any discussion of guilt or innocence, to separately write down a paragraph or two of their summary as to why each respective side should have won or lost the case, and then the readings of these paragraphs by the selected juror foreman or similar, will provide valued information as to the fairness of these jurors, so those that turn in papers that cannot come up with even one valid reason why a particular side was right or wrong, are those that have probably come to that conclusion very early in the process and thereby have shut the door on all contradictory evidence to that theory, while remembering or noting only the evidence which supports their favored side. On the other hand, a juror that can make a valid and fair case for either side is the epitome of someone that weighs evidence properly, listens well, and thereby represents the type of juror that will render the most defensible decision based on the evidence presented properly weighed and objectively evaluated.