Amelia Earhart: Never interrupt someone doing what you said couldn't be done

Never interrupt someone doing what you said couldn't be done.
- Amelia Earhart

OK, so the wording is a little sarcastic, but the idea is important. If you believe that something is impossible, you have just made that task impossible for you to accomplish, but you are likely to watch in amazement as others make it happen. Very few challenges can resist insight and perseverance for long.