My IT mistakes: Things I would rather forget

In IT, you can guarantee that there will be bugs, mistakes, glitches and all kinds of other foul things that will occur over time.  Here are a few that I attribute to my own mistakes.  I can only hope that someone else may learn from these.

1. Did a technology refresh of many of the libraries in an application which performs a form of single-sign-on(SSO) to another application.  The SSO was tested and worked fine but the newer HTTP libraries handled browser detection differently.  The updated SSO system was deployed to production.  The end result was parts of the SSO target application failed to function because of problems with browser detection which had to occur during the SSO process.  
1. I learned that when dealing with SSO functionality, the target application should be thoroughly exercised as well.
2. Turned on some extensive logging and ran out of disk space.
1. I learned to configure logging systems to rotate logs and maintain a fixed maximum disk usage.  I now archive/compress logs off to another filesystem if longer term retention is needed.

to be continued.