No one lives forever. We all have to come to the realization at some point in our lives that we're going to die. The DNA in our bodies has a maximum lifespan of around 125 years, but health complications and other issues can end human life as soon as 40-50 years old.
So what happens to your body when you die? A lot actually.
Not only will death cause your brain to shut down, but the lack of signals to your sphincters and heart mean that bodily fluids will work their way out and blood will pool at the base of your body thanks to gravity since there's no longer any pressure to keep it moving.
Decomposition starts almost immediately, and is sped up by cell enzymes, which work to eat the body tissue away. Chemical reactions will cause gases to build up in your body, which may cause ballooning of the body.
Stiffness will occur for the first 24-48 hours as muscles relax and contract, so your body may become stiff in whatever position it's in.
Alas, although death isn't the prettiest sight, it's still a natural part of life that keeps life cycling around. We will have our time, and soon, it'll be the time of our kids and their kids after them.