restriction

restriction n.  A {bug} or design error that limits a
   program's capabilities, and which is sufficiently egregious that
   nobody can quite work up enough nerve to describe it as a
   {feature}.  Often used (esp. by {marketroid} types) to make
   it sound as though some crippling bogosity had been intended by the
   designers all along, or was forced upon them by arcane technical
   constraints of a nature no mere user could possibly comprehend
   (these claims are almost invariably false).

   Old-time hacker Joseph M. Newcomer advises that whenever choosing a
   quantifiable but arbitrary restriction, you should make it either a
   power of 2 or a power of 2 minus 1.  If you impose a limit of
   17 items in a list, everyone will know it is a random number -- on
   the other hand, a limit of 15 or 16 suggests some deep reason
   (involving 0- or 1-based indexing in binary) and you will get less
   {flamage} for it.  Limits which are round numbers in base 10 are
   always especially suspect.