“The world is moving so fast these days that the man who says it can't be done is generally interrupted by someone doing it.”
“Those who say it can't be done are usually interrupted by others doing it.”
“People who say it cannot be done should not interrupt those who are doing it.”
“You can't move so fast that you try to change the mores faster than people can accept it. That doesn't mean you do nothing, but it means that you do the things that need to be done according to priority.”
“Never interrupt someone doing something you said couldn't be done.”