All project managers have experienced a failure in one form or another. If anyone says otherwise, they are not being honest. By their nature, projects will fail at one point or another. Your well-thought-out and documented project plan will fail as well. What is important is that you understand why and act upon it. Killing a project that is bound to fail can actually be a success. If you know why projects or plans are likely to fail, then you will be better equipped to deal with potential project roadblocks.