Then God blessed Noah and his sons and told them, “Be fruitful and multiply. Fill the earth. Gen 9:1
Then they said, “Come, let’s build a great city for ourselves with a tower that reaches into the sky. This will make us famous and keep us from being scattered all over the world.” Gen 11:4
Boy, that didn't take long. Two chapters and we're right back to self-centered rebellion. Maybe they thought, "If I build a tower, then God can send all the floods He wants and we'll be ok anyway." That would be funny if it weren't so pathetic--like toddlers covering their eyes so you can't see them.
I once heard a famous football coach speak on Genesis 11:6: 6 “Look!” he said. “The people are united, and they all speak the same language. After this, nothing they set out to do will be impossible for them!" This verse literally changed his life. From that point on, he did everything in his power to learn what it takes to get people united and working together, because even God said that when we are united, nothing is impossible. Unity is a great thing, unless we are silly enough to think we can be unified against God. It's the biggest thing Jesus asked His Father to grant to us:
21 I pray that they will all be one, just as you and I are one—as you are in me, Father, and I am in you. And may they be in us so that the world will believe you sent me. 22 “I have given them the glory you gave me, so they may be one as we are one. 23 I am in them and you are in me. May they experience such perfect unity that the world will know that you sent me and that you love them as much as you love me. John 17:21-23
The unity Jesus desired was a unity with God, not against Him. That's what set Abram apart from all his kindred. Because he believed God was trustworthy, he was not afraid to be in unity with God (obedience), even if it meant leaving home to go a long way away. That's a unity God can and did bless with a heritage that lasts through eternity. In the end, the makers of the tower of Babel remain nameless while nearly all the world has heard of Abraham.
One final note, Abram would have done well to value unity within his own household as well. He was more loyal to his own hide than his wife, which left her in danger of molestation from the Egyptian king--and this won't be the last time. God was loyal to her and embarrassed Abram on her behalf, but it's going to take two generations to get the idea through to them that you protect your family as yourself. I don't know why Sarai didn't balk at the idea. Maybe she really believed Abram was in danger--we women will do anything to protect the ones we love, even when it means putting ourselves in harm's way. This definately becomes an example of the truth of Gen 2:18:
18 Then the Lord God said, “It is not good for the man to be alone. I will make a helper who is just right for him.”
In this case, Sarai's silence left Abram alone to make the decision and that wasn't good--for him or her. It wouldn't have been right for a God-given helper to be argumentative or quarrelsome, but it is no help at all to say nothing. Sometimes that also means that if the husband wants the help God said he needs, he needs to encourage insight from the one who is "bone of my bone, flesh of my flesh." Wives aren't always right, but since she is knit to you as one flesh, it is foolish to miss out on their perspective--she wants the best for both of you too.