Modern medicine has progressed to the extent that we're mostly able to give cancer a nice good fight now, but it's still one of the scariest things to experience, whether you have it yourself or just know someone who does. Its unpredictability and prevalence makes it by far the most feared disease in this world, and also by far the second funniest thing in the world to Daniel Tosh.
4. War/Terrorism/Nuclear Weapons/All of That
Life is a triumph every day that we're able to avoid one of the things listed below. Unfortunately it all counts for nought if someone important somewhere decides to blow us up. These kinds of conflicts aren't just very real and very dangerous, they're super frustrating, because very often the people inevitably caught up in the violence haven't had much to do with what started it all in the first place. And sure, world peace would be nice and all, but, then again, we'd never get to see what happens on Homeland. It's a Catch 22.
3. Your Parents Dying
Your parents have known you since the day you were born, and you've literally never gone a moment without them (in the sense that, like, they're there for you. I get that they weren't around when you went to the bathroom and stuff.) So the idea of never seeing or speaking to them again is a big adjustment to make, especially if you're on one of those cell phone family plans. What happens?!
2. That Brain-Eating Parasite
I'd wager a bunch of people didn't know this was an actual thing before they voted for it, because OBVIOUSLY. It EATS your BRAIN. I don't even like watching human beings eat yoghurt, so the idea of a weird little insect feeding on the grey wrinkly flesh that contains everything I am might just be the worst thing that's ever happened to me. The worst part? It could be happening right now. To you. Sitting there reading this as you're slowly erased by a gross creature feasting on your memories. Sorry, that was mean. I'd tell you not to worry but in all honesty I can't be sure that really isn't happening. Good luck!
Knives, disease, war, parasites, none can compete with the simplicity of being trapped underwater until you die. It takes a good while to lose consciousness through lack of oxygen, so you have a good long while while you're drowning to know what's happening, and what's likely going to happen next. You also won't be able to see or hear anything, meaning all your energy is going to be used focusing on the fact you can't breathe, and that slowly but surely your brain is shutting down piece by piece. My commiserations go out to all the unplaced competitors, as well as anyone who's ever drowned, which we've established is a terror unlike no other. Sincere congratulations to drowning, which has rightfully topped the most horrible and depressing poll of all time.