Why learn hexadecimal? [closed]

Question

I've taken quite a few intro programming classes in my day, mostly just to get my feet wet in every different kind of programming I find. Not surprisingly, just about every class runs through the same format : intro to hardware, intro to software, and then you get into the actual programming. While understanding how the hardware and software works is very important, I've always been confused by one topic that has been in every single course.

In the intro to software section I've found, without fail, they always put large emphasis on being literate in binary, hexadecimal, and sometimes even octal number systems. I understand that it's good to understand what these things are, and how a computer would interpret them, but I've never found myself actually needing to know how to read and write any of those number systems. Really, the only time I've seen something other than base 10 is for colors in CSS, which is even easier if you use something like www.colorpicker.com

Have I just been ignorant of the wonderful uses of these non-base-10 number systems in the programming world, or is just an old tradition to include these sections in all programming textbooks? Does anyone have a good example of where the average programmer would actually use an octal number?