When Person A states that they have faith in Person B, they are stating that they trust Person B. Since trust is the issue here, let's focus on that. In order for Person A to trust, there must be a foundation for that trust. Usually, Person B has established in the past that they are trustworthy (usually by verification of the truth of claims and/or following through with promises). Also Person B knows something that Person A does not know. In order for trust to be exercised, there must be a foundation to establish trust, and something that is unknown to justify acting upon the foundation of the person's trustworthiness.
So, as long as there is a foundation of trust established and something unknown to Person A, faith can be placed. If either is missing, then faith is not what is being exercised. If a foundation is missing, gambling would better describe the action. If an unknown is missing, agreement is taking place.
Since faith is basically trust; faith, by virtue of its foundation, is based on reason: "Person B has been trustworthy in several past experiences; therefore, it is reasonable to conclude that I can trust them with this new unknown". There is nothing "blind" or "illogical" about faith. Of course, there is plenty of room for misinterpreting past experiences (and thus foundations for faith), and this is why many people have misplaced their faith. However, a misplaced faith is different from a gamble.
When faith is misplaced, we can identify it by looking at the previous experiences that laid the foundation for the faith. Interpretation of past experiences must be done in light of the person who is the source of those experiences (Person B). What I mean here, is that if we do not have an accurate understanding of the person's character (thus wrong expectations), our interpretations have a much higher possibility of being incorrect.
One of the main misunderstandings of who a person is (thus wrong expectations) in religious debates is that God claims to desire the comfort of all people to the exclusion of all other things. When people experience suffering in the world, they interpret it as God not being trustworthy (some even take it to mean that God doesn't exist, but that is another discussion). This causes them to look elsewhere for something to trust with the unknown. Many people have alternatively placed their faith in mankind. However, the failures of mankind just in the past century demonstrates that faith in mankind is misplaced. Our understanding of mankind did not allow for the failures- which means that there was a misunderstanding of the nature of man (thus wrong expectations). These two misunderstandings have left a gaping hole- man cannot trust anything or anyone.
This is the danger of not understanding the nature of who is responsible for the experiences that we use to interpret the reliability of the person. A misunderstood nature will lead to a misplaced faith. Now, faith can become a gamble at this point: when a person possesses the evidence that man is untrustworthy, yet still places their trust in him. If we decide to allow our decisions to go against the evidence, we have switched away from reason without a good reason.
If people were willing to understand the Christian God as He is (not as we want Him to be or think that He is so we can reject Him), man would find that trust in the Christian God is a very reasonable faith.
More great blog posts about faith:
Biblical Faith vs. Blind Faith- Evan Minton
Challenging Atheism's Definition of Faith- Robin Schumacher
Why Do People Completely Misunderstand the Word "Faith"?- Eric Chabot
Does the Bible Teach that Faith is Opposed to Logic and Evidence? - by The Wintery Knight
Rebuttal to Bill Maher's Claim - by Robb Berry
Why Both Skeptics and Theists Have to Exercise Faith- Eric Chabot
Related articles:
Do You Rely on Authorities?
Is Blind Faith Biblical?