There has been a bunch of stuff written about the “Broken Windows” effect - the way that even good people will begin to do bad things if everything else is bad around them. In areas that look badly maintained, people tend to drop more litter. Where people are obviously flouting the rules others are more likely to bend them themselves. And in software, when you are working on bad code you are more likely to write more bad code. I first stumbled across the idea in an interview with the Pragmatic Programmers , but the evidence given is fairly apocryphal. So I was pleased to find something more definite . And it does make for interesting reading. The effect is indeed real, and significant. The number of people breaking social norms when they see that others have done something similar more than doubles. It's the 'no-one will notice another little bit of mess' effect. The study quoted in the article reinforces the need to maintain a high level of hygiene in your software.