A colleague of mine wanted to reduce the repetition in this fragment of C++:

funcA(false);
funcB(false);
funcC(false);
funcD(false);
funcA(true);
funcB(true);
funcC(true);
funcD(true);

and, in a burst of sheer genius, came up with this solution:

for (bool status = false;
          status <= true;
          ++status) {
  funcA(status);
  funcB(status);
  funcC(status);
  funcD(status);
}

He then scratched his head as the program looped for eternity.

Who could have predicted that a common-or-garden bool could have so many values? Let me count them. The possible values of bool are false, snopes, statistically_significant, almost_true, true, very_true and tautology. ++tautology gives you tautology right back, as any fule kno.