Doubt is a virtue, people.
By this I do not mean to say that we should seek to doubt everything without further thought. Courage is also a virtue, but to seek to be maximally courageous without further thought would kill you very quickly. Just as wise courage does not consist in doing everything dangerous that you can find, so also wise doubt does not consist in giving no credence to anything. Rather, doubt and evidence play counterpoint to each other; doubt creates room for new evidence and the desire to seek it.
Doubt is connected both to courage and to humility. It takes humility to concede that you might be wrong, humility to be open to the ideas of others and to resist the temptation to assume that the conclusions you have reached to date will always be as sensible as they currently seem to be.
But courage is perhaps the most difficult aspect of doubt, and lack of courage rather than lack of humility is surely the biggest reason why none of us are perfect doubters. The ideas on which you build your life can be like a platform above an abyss of doubt, despair, and purposelessness. Subjecting the ideas on which you build your life to skeptical criticism is like jumping on the structure to see if it holds. It can, with good reason, feel like tempting fate.
Doubting yourself is psychologically difficult enough that nobody could be expected to doubt themselves completely all the time. Indeed, it takes work. As soon as we find the foundation to be unstable we have no choice but to shore it up somehow, and if we are to hold to the ideals of doubt, a quick-fix refusal to look is out of the question. Instead, we have to try to find a better way of living. This can be more or less time consuming, depending on the problem. Nobody can force you to do it. The only way you could possibly survive a major change in this area is to take it in your own time.
Now imagine if I told you that you didn't need to doubt. Imagine if I said "You can take this as absolutely true and go build your life on it, no need to question." Would you be tempted? Would you take the opportunity to try to escape fear of the abyss?
I don't know if it works. But it's wrong. It's lazy. In some cases it has terrible consequences, as the dubious history of so many religions and the famines (to say nothing of terrible abuse of human rights) caused by communist regimes clearly show.
When religions explicitly sanction a complete lack of doubt, such blatant encouragement of laziness is in stark contrast to the bold ideals of virtue that religion usually demands in other areas. While you must be constantly on your guard against greed, anger and jealousy, you may have as much faith -- I spit the word -- as much faith as you like. Often, it is worse. Being allowed to be intellectually lazy is bad enough, but to be encouraged to be so! I am told that faith can be difficult. I dare say it is. I dare say complete gluttony would also be rather difficult. But it is also, pardon the phrase, bloody stupid.
Doubt is tough. Nobody ever said that virtues are easy! All we can do is try our best to be both open and discerning at the same time.