Because I came from pioneering stock here in the U.S. that first migrated to the eastern United States in about 1725 the words "Question Authority" became a household word. People who asked questions usually lived. People who didn't ask questions often died. This was just what it was like to be a pioneer in America. Because just like now there was always someone there trying to take advantage of you or kill you, (one or the other).
So, believing everything that anyone says is always not a good idea. However, there are some times when questioning might not be as useful as others. If a law enforcement official asks you to do something one might have to learn to be polite in some circumstances and intelligent about the questions one asks to stay not beat up and not dead. So, this is something to think about too.
So, questioning authority is more useful when dealing with average people, teachers, doctors, nurses, Lawyers and the like. When you question officials other than police or firemen it can be more useful and less dangerous.
But always try to know your rights so no one can bamboozle you into thinking something that might be dangerous or lethal to your life or future.
So, the first step in questioning authority must be to educate yourself so you know your rights in all situations. If you don't know your rights you will always be vulnerable to mayhem or death even in the U.S. of America. Knowing your rights and how to always protect yourself, your family and your children will save your life and their lives more than once during your lifetime.