We lie. We cheat. We bend the rules. We break the rules. And sometimes, as we’ve seen in Greece, it all adds up. But, remarkably, this doesn’t stop us from thinking we’re wonderful, honest people. We’ve become very good at justifying our dishonest behaviors so that, at the end of the day, we feel good about who we are. This tendency is only getting worse, and, as innocent as it may seem, the consequences are becoming more apparent and more serious.

Cheating has less to do with personal gain than it does self-perception. We need to believe that we’re good people, and we’ll do just about anything to maintain that perception. Sometimes, this means behaving in ways that align with our sense of what is right. Other times, it means crossing that line, but turning a blind eye to our behavior, or rationalizing it in some way that allows us to believe it’s OK.

Let’s say your friend, who is not looking their best, asks you how they look, and you don’t want to hurt their feelings, so you lie. You fudge it. You don’t necessarily say, “Wow! You’ve never looked better,” but you don’t tell them the full truth. And you have no problem rationalizing your fib: It’s the right thing to do, because you would never want to hurt your friend’s feelings. Perhaps you used more neutral complimentary terms, or didn’t look them in the eye at that particular moment. These sorts of details would make it easier to justify your well-intentioned lie, and help you sleep at night without giving it a second thought.

The same kind of self-deception applies to wider-scale cheating, although the motivations are usually different. In more professional scenarios, our dishonesty is typically fueled by the desire for wealth or status rather than concern for the reputation of others. Greed is a powerful motivator.

About two months ago, American businessman Garrett Bauer was sentenced to nine years in prison for insider trading. Garrett was one of the people I had spoken to in researching the nature of dishonesty, and to see the consequences of his actions catch up to him that way was a brutal reminder of just how out-of-hand cheating can get. Garrett traded stocks on insider information for about 17 years. He started off small, as people tend to do, and never considered that he might get caught. As time went by, it got easier and easier for him to cheat the system free of guilt. But then he got caught, and now it’s too late to correct his mistakes.

That night, after his sentencing, I couldn’t sleep. I curled into the fetal position – the world looked terrible to me. I had spent the day before in New York giving talk after talk about cheating and dishonesty, how widespread they are, and how little appetite we have to start changing things. With all that cheating weighing on my mind, Garrett’s sentence was an additional terrible blow. It was overwhelmingly sad, and a very painful night.

The consequences of this sort of cheating are even more severe when the network of contagion is larger. We see this when we look at Greece, where masses of people have been cheating a little bit everywhere, and it’s added up. What this shows is just how contagious dishonesty can be. When we see somebody else cheat, especially if they’re part of our own, internal group, all of a sudden we figure out that it’s more acceptable to act this way. It’s not that the probability of our getting caught has changed – it’s that we’ve changed our mindset, convincing ourselves that the act itself is actually OK. At some point, you just think, “This is the way things are done,” and you go with the flow.

One woman from Greece recently told me that she was selling her apartment and she was considering whether to sell it legally (and pay taxes) or illegally (without paying taxes). She quickly recalled that she had bought it illegally, and that she was going to lose money if she would turn around and sell it legally – not to mention that in her mind she would be the only person in Greece paying taxes on real-estate property.

When everyone around you is cheating the system, what’s your motivation to be the one not playing along? And why change now? Why not make changes next month, or next year, instead?

This mentality is accentuated in Greece because it’s not just the everyday citizens who have been cheating – the government has been fudging the books. When cheating is that entrenched in a country, what can you do to stop it? It’s incredibly naïve to think that it will stop on its own. What Greece needs is something like the Reconciliation Act that South Africa adopted, focusing not on the travesties it has done to its people, but on starting fresh.

Every day, people are finding new and more creative ways to cheat, and to justify their dishonest behavior, regardless of the negative impact their actions might have on others. What’s most worrying about this trend is that we still fail to grasp the extent of our dishonesty. But it doesn’t have to be like this. If, on a global scale, we worked to understand the root of our dishonesty, and motivated each other to overcome it, we could do much better.