@Finn dAbuzz,
That's not true Finn.
I don't say that I am "largely certain" that I am right unless there is evidence supporting my certainty. Believing you are certain when you don't have a factual basis for this certainty is dangerous.
And that is why faith is dangerous.
Let's look at your examples.
1) When there is a dangerous threat that requires an immediate response, the fight or flight response is an important evolved trait.
This isn't faith. It is panic. We have a panic response because when it is right, it saves our lives, and when it is wrong, it generally does nothing worse than make us look funny.
2) Having a fear of something where there is no factual evidence it is actually dangerous is not so useful. This is called prejudice or intuition... what you call it doesn't matter. Rational people challenge their fear... even if you keep the fear you should realize that you are probably wrong (since there is not factual basis for your fear).
3)
There is nothing wrong with being unsure. And there is nothing wrong with making decisions where you don't have enough evidence to be certain. The key here is to be honest that you don't really know... that way you can question your decision when new evidence appears or when the cost of your decision gets to high (i.e. when you are hurting other people).
4)
It is very bad to be certain when you don't have evidence to support your certainty. Being certain means you stop questioning, you stop counting the cost of your decisions.
This is why faith is behind wars, and hatred, and prejudice. People who are certain can justify there actions... and since they are not basing their certainty on factual evidence, the facts don't matter.
Of course faith can motivate both good actions and bad actions. The problem is since faith is certain, there is no questioning when the beliefs are not justified by evidence or new facts appear.