Seriously, who thought that case sensitivity is a good idea in standards? Especially ones that deal with email. I’m currently affected by a bug that causes me to be unable to send email to certain mailing lists because the system actually does what the standards tell it to do.

One thing that always raises a red-flag (or at least a pretty bright yellow) for me is when I am reading a spec / requirement and I catch a whiff of case sensitivity. I realize that there are places where it is necessary (keywords in languages for example), but in most places it adds an unnecessary layer of complexity to your application which means the user has more stuff to learn and retain. Less of which I consider a Good Thing.

Take for instance, the difference between the unix filesystem and the windows one. On unix, case matters. A lot. So file.txt and File.txt and FiLe.txt are all possible in the same directory. Not only does this cause confusion as to what things are what, but even if there is only one instance of a file you need to make sure you reference it correctly and that how it is formatted doesn’t change. Contrast this to the windows behavior. One instance of a filename per directory regardless of case of the component characters and your can reference it in pretty much any way you want. Much easier, and consequently nicer to use.

Both ease of use, and niceness of use are two factors I internally measure when trying to asses the Quality of something.