Why do some people commit suicide just because of a failure?

Tweet

This one is a few years back. That time, I was still in elementary. I have heard news about suicide. Some commit suicide because of money, love, etc. But its very weird when some people commit suicide just because they failed in the bar/board exam. Why is that so? Do they know about "Moving-on"? What sensitiveness?! I do really fail some subjects but I really don't think about this stupid act. And most of this guys are genius people. Its just a failure, but they think it is a mortal sin for them...