In his book Predictably Irrational, researcher Dan Ariely claims that most of us are masters at deceiving ourselves and justifying our actions. In particular, we often make our decisions based not on what's right, but on what we want.

Ariely tells his own story of buying a car. "When I turned thirty," he writes, "I decided it was time to trade in my motorcycle for a car, but I could not decide which car was right for me. The web was just taking off, and to my delight I found a site that provided advice on purchasing cars." Professor Ariely describes how he answered all of the questions on the website, which then recommended that he purchase a Ford Taurus. He describes his reaction this way:

The problem was that, having just surrendered my motorcycle, I couldn't see myself driving a sedate sedan. I was now facing a dilemma: I had tried a deliberative and thoughtful process for my car selection, and I didn't like the answer I got. So, I did what I think anyone in my position would do. I hit the BACK button a few times, backtracked to earlier stages of the interview process, and changed many of my original answers to what I convinced myself were more accurate and appropriate responses .… I kept this up until the car-advertising website suggested a Mazda Miata. The moment the program was kind enough to recommend a small convertible, I felt grateful for the fantastic software and decided to follow its advice.

Commenting on what he learned in the process, Professor Ariely says, "The experience taught me that sometimes we want our decisions to have a rational veneer when, in fact, they stem from … what we crave deep down."

Possible Preaching Angles: (1) God's Will—With our tendency towards self-deception, we sometimes determine God's will based on what we really wanted in the first place. In other words, God's will = what we want. (2) Desires, sinful—Although some of our desires are good and healthy, some of our desires are based on the sinful bent of our heart.