Why Do Bad Things Happen To Christains? The answer is simple, because God loves us. Weird right? First off, I should state that we do not exist for us but too share his Grace and Love.
God understands the nature of Man and we Humans beings have the tendency to devaluelize the things given to us especially when in abundance. God knows that when he showers his blessings on us, we eventually reach a point where we wouldn't appreciate as much as we ought to and that would make us lose our reverance for him. Imagine giving your own children​ everything they ask for without any limitations? Wouldn't​ they get spoilt eventually.
Hebrews 12:6 Says "Because the Lord disciplines those he loves, and punishes everyone he accepts as a son." God loves us so much that he doesn't want us to perish by having that feeling of contempt so he sends us challenges and hardships for a short while.
When you lose something you once had, you cherish it more - This is a typical human characteristic. When this period of hardships fades away, we feel inclined to love God more and appreciate his grace.
Your triumph and testimony from hard times will not also inspire you but also the people around you. So dear brothers and sisters, when you are going through a tough time, first of all have in mind that it is temporary and God is trying to strengthen your love for him so you do not lose sight of his.

Bad things happen to everybody including animals no matter your religious affiliation even if you’re an agnostic... it’s part of nature

Yeah... but why Christians?? That's what this thread is all about?

In this world we will have troubles, but He(Jesus) has overcome the world.