Related:

• Constants aren't; variables don't.
• Variables won't; constants aren't.
• Osborne's Law: Variables won't: constants aren't.
• A math student is pestered by a classmate who wants to copy his homework assignment.
  The student hesitates, not only because he thinks it's wrong, but also because he doesn't want to be sanctioned for aiding and abetting....
• Quantized Revision of Murphy's Law: Everything goes wrong all at once.
• Murphy was an optimist!