How can God use such messed up people?

So the Lord told my mentor to tell me to start over in my reading. I just started over in August so I haven't really read that much so not too big of a deal and if that means that He's goig to reveal even more to me, that's awesome!
So I went to Genesis at first and my heart just wasn't in it at all so I went back to Matthew. The beginning of Matthew is the geneaology of Jesus. I got to verse 5 and stopped. Rahab, a former prostitute, go to be in the geneaology of Christ. Amazing! Also I don't think I knew Boaz was her descendant. It says her son here but not sure if that means actual son or descendant. I read Ruth and some of Joshua and still not sure. I remember Boaz being the type of man we all wanted to marry in Bible study. We would all talk about finding "our Boaz". So this man who we all wanted to marry was the descendant of a prostitute.
This then lead me to think that might be the reason he was such an awesome man to begin with. He knew God's grace and mercy first hand through his family. He heard a story of a woman stuck in sin who risked her life for spies and the Lord saved her and her family. He heard how the Lord changed her and gave her a second chance. This could be why he was so merciful to Ruth, a moabitess. He knew about second chances. When I reread Ruth it was evident why we all wanted to marry a Boaz. His character is awesome.
I then started to think about how we Americans, especially Christians, try to make our families look perfect. We don't want anyone to know that our families are struggling to stay together or members of our families are having problems. Why is that? It seems like God uses the most messed up people in the Bible. Why do we hide our messes? We can let our messes be our message if we let God work through us. Why do we think because our families have had issues in the past that we can't be used by the Lord? It seems like God uses the most messed up families for His glory. He used a prostitute and His Son came from her family line. Abraham is the man we as Christians look up to but he slept with his wife's servant to have a baby, not trusting the Lord's promise. He uses our mess ups to reach others and bring glory to His Name. How amazing and refreshing is that!!!