None - Unless You Let It
Professed Christians have marriage problems, job problems, addiction problems, just like non-Christians. The stats are pretty much the same. So, you could say that it does not make any difference at all, and you would be right, but then you would be wrong.
One of the problems is that it is easier to do the physical things to look like a Christian, but harder to live like Christ. There is a world of hurt out there. I know. I have walked in it, and am tempted all too often successfully to walk in it everyday, like right this very minute.
In my darkest times, my mother prayed that God would hit me over the head with a baseball bat, literally, and who could blame her. Fortunately for me, God was more gentle than that for many years, and then he hit me over the head with a 1994 Ford Windstar van. Even then, maybe especially it took time for me to wake up. I mean, heck that hurts.
But along the way, the Holy Spirit happened to me, like he did to the early Christians, and like He wants to do for every man, woman and child living on the earth today.
You can pretend that God is dead, or never existed. It is your choice what you believe, but what you choose does not make it any more real or true.
God believes in YOU, and he made YOU in His Own Image, and wants to share eternity with YOU.
But, you have to do your part. You have to want Him in your life. You have to choose Him over choices that look very attractive in the moment.
What difference does being a Christian make? It makes all the difference in the world. If you accept Christ into your life, your eyes see things differently. You live differently. You LOVE differently, and LOVE is all there is in this world that has any value for us.
The fancy house you live in could burn down. Even if it doesn't you will move or die, and it won't matter after that. The fancy car you drive will rust, or wear out, and will be just a memory. The job you have that pays the bills will be gone too. You may retire; you might get fired. The company might go bankrupt or be bought out. Or, the economy can stay in recession or worse.
The one you love today will grow old, as will you. Your health will deteriorate. All things on this earth are temporary.
But the love of God is eternal.