Why wars happen?
Why cannot we be friends?
Why did God let wars happen?
You can think: "If God loves us then He have to care us".
God really loves us, but He doesn't change our lives.
If we want to have happiness, then we have to be friends of our enemies (Matthew 5, 43-45).
You will love your neighbour and hate your enemy.
But I say this to you,
love your enemies and pray for those who persecute you;
so that you may be children of your Father in heaven,
for he causes his sun to rise on the bad as well as the good,
and sends down rain to fall on the upright and the wicked alike."
We can decide for ourself, but we can listen God before do anything.
If you ask to God: "Help me, my Father! How can I do it?", He will say what you have to do.
Do the test, say to God your problems and pray a Hail Mary. After, open a Bible in any page and read the first thing that you see.