A colleague from 15+ years ago had an unfortunate habit of using filenames like &quot;poo&quot; or &quot;shit&quot; for writing debug output.<p>One morning, the inevitable happened: a very angry client phoned up complaining that his site was swearing at him.<p>It turned out that the debug log had filled up, causing the site to crash on load, displaying only a single line:<p>CANNOT OPEN SHIT<p>The lessons you learn early on in your career.