How To Write Unmaintainable Code

from page... zOMG this is evil!

CODE THAT MASQUERADES AS COMMENTS AND VICE VERSA

Include sections of code that is commented out but at first glance does not appear to be.

      for ( j=0; j < array_len; j +=8 )
      {
         total += array[j+0];
         total += array[j+1];
         total += array[j+2]; /* Main body of
         total += array[j+3]; * loop is unrolled
         total += array[j+4]; * for greater speed.
         total += array[j+5]; */
         total += array[j+6];
         total += array[j+7];
      }    

Without careful attention , would you notice that three lines of code are commented out?

I like this one:

Object oriented programming is a godsend for writing unmaintainable code. If you have a class with 10 properties (member/method) in it, consider a base class with only one property and subclassing it 9 levels deep so that each descendant adds one property. By the time you get to the last descendant class, you'll have all 10 properties. If possible, put each class declaration in a separate file. This has the added effect of bloating your INCLUDE or USES statements, and forces the maintainer to open that many more files in his or her editor. Make sure you create at least one instance of each subclass.

    Underscore, a Friend Indeed
  Use _var and __var in identifiers. 

Even better when it's sometimes __ and sometimes ___ - you can never tell which it is at a glance. (Python is great for this one!)

A classic.

My favorite is "Properly-written code never fails, so exceptions are actually unnecessary."

This should be translated in a few languages I can think of.

I'm going to copy and paste this into any empty or default text README.md's I find in projects I'm assigned to work on. Perhaps Github should also post it as the default README.md for any new project.

These are all great suggestions, because it's very often (always) that management assumes they know what your software does given the output.