I recently started a new job and as is typical of all jobs, if you've left, you get blamed for everything. Not long after I started there was a change required for an app (web based) that we maintain, and it was quickly pointed out that the actual code for this site had been lost a long time ago, and the only changes we could make to the it were ones that required changes to mark-up [it was a pre-compiled site].
Being new, I needed a little help finding my way around the code, and enlisted the services of one of my colleagues. Made my changes, and then re-enlisted his help to deploy it. While prepping for the deployment (getting the app on the QA server) we discovered that there were actually 2 different, very similarly named, folders in our source repository. It transpired that for the last year or so, mark-up changes had been made to the site directly, and these were the only differences with the code in the slightly incorrectly named folder in source control. So we did have all the code, and can now properly support the site.
This put me in mind of a trick we played on a junior programmer once in a previous job, where we told him he couldn't/shouldn't do a certain thing in code as this would likely bring the server to it's knees and cost the company thousands of pounds (a gag that last months :-). And another one in the first programming job I took on - the batch commission run was just going to crash once a month and there was nothing to be done about it, causing a call out, and call out compensation for the on-call guy (a bug I fixed as soon as I became the on-call guy - 2am call outs don't work for me).
So I was wondering... What other programming fallacies/myths are out there that are worth sharing?