One man gives an account of lying for a living. One of the interesting things from a Christian point of view is what he says about lying to yourself:
The jewelry business—like many other businesses, especially those that depend on selling—lends itself to lies. It’s hard to make money selling used Rolexes as what they are, but if you clean one up and make it look new, suddenly there’s a little profit in the deal. Grading diamonds is a subjective business, and the better a diamond looks to you when you’re grading it, the more money it’s worth—as long as you can convince your customer that it’s the grade you’re selling it as. Here’s an easy, effective way to do that: First lie to yourself about what grade the diamond is; then you can sincerely tell your customer “the truth” about what it’s worth.
This is how sin works, it’s not that we don’t know we’re sinning, it’s that we do but persuade ourselves we’re not. How much do we need God’s Spirit to cut through our lies with the Word of God so that we can repent and fix our eyes on Jesus. (via)