Twist endings in movies may shock the audience or pull the plot in new directions, but that doesn't mean twist endings in films always make sense. Plenty of twist endings ruin the movie, and in many cases, this happens because the sudden revelation lacks logical coherence.
Far too many movies with twist endings make it clear that filmmakers want an easy way to trick the viewer. Some movie plot twists put forth unspoken consequences that offer inadequate build-ups and explanations; others break far from the reality of the film and leave audiences wondering "why?" It's far better to provide an ambiguous ending so the audience can arrive at its own conclusion rather than shoehorning a terrible plot twist that makes no sense, whatsoever.