[blihp]

There's a lot of value placed on consistency and predictability both in civil and criminal law. If the law were arbitrary, then there really is no single set of rules that apply equally to everyone. So when a court decides X in a given case, any other parties going to a court in the same jurisdiction with the same set of facts and circumstances expects the case to be decided in a similar way. Of course, that's the perfect world theory and caveats apply.

[saalweachter]

I would emphasize "any other parties": one of the goals is that if I or if someone who is rich, famous or influential were to be defendants in court cases with similar facts, we would receive similar judgements - who the defendant is shouldn't matter, and paying attention to relevant precedents helps ensure that.

I would also mention that the internet tends to misuse precedent in the same way, well, the internet misuses logical fallacies. Finding a precedent you think is applicable to a court case doesn't mean the verdict is decided. Both sides, assuming they have competent lawyers, will submit numerous precedents they believe favors their side, after all. It is up to the courts to decide whether the precedents are applicable and whether to apply the precedent in any give case; precedents inform the court, they do not replace it.