He or she may disregard or discount what you feel is the strongest part of your case, and give great credit to your adversary's version of things. This raises a serious question about justice. In support of this concept, tell the truth, the whole truth, and nothing but the truth. There is some weakness in every claim. If you tell your story with its flaws exposed, the judge is much more likely to believe it.
Judges are human.
Being a judge, I know that deep down inside, every one of us has a heart of gold. It may just take considerable digging to reach it. Because judges are human, they may, from time to time, make a mistake in judgment. There are other intangibles to consider. I have not done any research on this, but I am suspicious that even the best judges may unconsciously favor certain kinds of people over others.