Related:

• This can't happen Less clipped variant of can't happen.
• can't happen: The traditional program comment for code executed under a condition that should never be true, for example a file size computed as negative.
  Often, such a condition being true indicates data corruption or a faulty algorithm...
• Accidents can happen.
• If you don't want it to - it CAN happen.
• It's a knockout tournament and anything can happen.
• People can fly. Anything can happen.
• For medium number systems, we can expect that large fluctuations, irregularities, and discrepancy with any theory will occur more or less regularly.
  (This is more succinctly expressed by Murphy: Anything that can happen, will happen....
• dead code: n. Routines that can never be accessed because all calls to them have been removed
  or code that cannot be reached because it is guarded by a control structure that provably must always transfer control somewhere else....
• Anything that can happen will happen, unless your test plan provides for it to happen.
  -- Weinberg's Programming Principle #3...