In 4:18, after Hashem gives Moshe instructions about going back to Egypt and talking to Pharoah, etc... Moshe goes back to his family and Yisro and he tells them he has to go back to Egypt to see how they are doing there....
Why did he not tell them the truth? Was he afraid they would not believe him? would they try to talk him out of it? would they think he was crazy?
This shows us that when a person has a plan, when he is working on a big project, don't tell people what you are doing. Even those close to you. They will steal your thunder, they will try to talk you out of it, they will ruin it somehow. Get the project rolling and then tell them when they can no longer ruin it for you.