We all know that death is a part of life. Unless you're like 5 years old, in which case: A) What are you doing on Cracked? B) Go get your parents to buy you a goldfish and C) Sorry about your goldfish. Death is a part of life.
Cracked has already covered a few ways the universe can kill us, without warning. But that list is merely a fraction of a fraction of the countless ways the universe does not want life to survive. Most of the universe can kill us instantly simply due to radiation, heat or cold. Most planets' orbits are unstable and most planets are doomed. In fact, all planets are doomed because all stars are doomed. In fact, all stars are doomed because the universe is, in all likelihood, doomed.
And that's ignoring how dangerous just the Earth is. We can't even safely inhabit 2/3 of the planet's surface. The planet is bombarded with earthquakes, tsunamis, volcanoes, hurricanes, et al. We've already seen mass extinctions due to climate change, disease, ourselves and asteroids. We are barely even here yet, as it took 3.5 billion years to achieve multicellular life. The fact is, we're inching along a thread, and we're always just hanging on by it.