You may think that an authority figure you are working with should not be challenged. You may think you don't know enough or have the right experience to lock horns with this individual, even though you can clearly see that the direction they are leading you is wrong. Yet if you don't speak up, you will keep heading down that path, and that would be a waste of your time. So, what could it hurt to say something if you do so with tact, respect, and diplomacy? At the very worst, they won't listen. At the very best, they'll take your advice.