Even if the worst happens on our shores (war, earthquake, tsunami...) I have the peace that passes all understanding. He is in control and our anguish and our life is but a breath, so it will only be for a short time. I pray you have that peace as well. Barnes Notes explains the peace that passes all understanding so well.
Which passeth all understanding - That is, which surpasses all that people had conceived or imagined. The expression is one that denotes that the peace imparted is of the highest possible kind. The apostle Paul frequently used terms which had somewhat of a hyperbolical cast (see the notes on Ephesians 3:19; compare John 21:25, and the language here is that which one would use who designed to speak of that which was of the highest order. The Christian, committing his way to God, and feeling that he will order all things aright, has a peace which is nowhere else known. Nothing else will furnish it but religion. No confidence that a man can have in his own powers; no reliance which he can repose on his own plans or on the promises or fidelity of his fellow-men, and no calculations which he can make on the course of events, can impart such peace to the soul as simple confidence in God.Are you saved? If so, then demonstrate that faith by clinging to Him, His promises, and His Truth. It is the best- the only- safe port in a storm! This is a great time in the United States to be peaceful, for others will see your calmness and through the grace of the Holy Spirit, they will ask you..."what is it that you have...?" and you will have the inestimable privilege of saying, "Let me tell you about Jesus..."
If you are not saved and you see someone who seems calm and graceful all the time, whose countenance seems glowing. (Exodus 35:35) it is because we have what Jesus has given us- His peace. We have been with God. We are no longer at war against Him but have become friends and sons of the Most High God. He imparts a peace that allows His children to look upon earthly circumstances with an eternal perspective.
Dear unsaved person, your good works are not enough to get you to heaven. Being really, really nice is not enough to get you to heaven. You can never do enough to get to heaven. The only way is through Jesus. You wonder what is it about Christians that makes them (us) seems o gentle and calm and they just look different? It's His peace. The sin struggle is over. The unanswered questions about why we are here and how the world was born and why people are like they are...these questions are answered. Right now would be a good idea to start praying seriously to the Lord above to resolve your internal war. You are a God-hater, perhaps actively but certainly passively. Do you want peace and rest from always striving and yet not knowing? (2 Timothy 3:7). He will provide His peace, upon repentance and faith in His resurrected self.