Phobias are one thing, but existential dread is fear on an entirely different level. From self-consciousness to thinking the Universe has it in for you, subconscious despair has the power to overtake our waking hours.

radbrad7 asked, What is something that really freaks you out on an existential level?

Submissions have been edited for clarity, context, and profanity.

What percentage of my life do I even remember? My childhood is a dim memory, but so are many average days of my adult life.

When I'm traveling by plane in a different country and I'm looking down to the ground and see cars, buses and everything driving around on the countryside or a city and I think to myself, down there are people living life exactly like I do and doing their everyday thing. Makes me think how big the world actually is and how tiny you are as a person! That freaks me out a bit.

I probably won't be remembered.

Everything is disintegrating. Nothing is immortal. The television remote on the coffee table will not be a television remote in enough time, even if that means thousands of years have to pass before it loses its intended form.

That whatever I did in the past are now just memories. Even yesterday. Even though sometimes it feels like my childhood just happened, it was 20 years ago and they're memories. Did those actions even happen? It's hard to explain the feeling.

How we could die at any second. Today, tomorrow, in a week, in the next five minutes, and nobody can stop it. Death is one of the true guarantees of life. I'm not sure what's worse: knowing you're dying or dying without knowing it.???????

That the tiniest, most inconsequential decision can completely change the entire course of your life.

Nearly 20 years ago, I needed some new shoes for work. As a poor student, I got the cheapest pair I could find.

Two days later, I was supposed to be going straight from work to a club with my friends when, halfway through my shift, the sole half ripped off one of the shoes. I didn't have enough time to get home, change my shoes and get back to work before everyone left for the club, so I just went home and gave it a miss.

That night, I started chatting with someone on a forum, a year later, went to visit them in America. Two years later I moved to America and we got married. Ten years after that we both moved back to the UK.

Had I chosen a different pair of shoes, I'd never met my wife, never moved to America and my life would be completely different now. Because shoes.

It takes an [admittedly microscopic] amount of time for your brain to process every stimulus that you receive. This means that you are never perceiving reality in real-time. There's the slightest delay between reality and your perception of it.

Chimpanzees.

I have never really been able to articulate this as well as I would like, but the existence of chimpanzees is deeply disturbing to me in a very indescribable fashion. They're basically us except for a few very minor and completely random mutations that made us slightly better at analyzing patterns and communicating with each other. Whenever I see a chimpanzee, I'm really confronted with the fact that we humans are just another animal species, mostly controlled by instinct and making our decisions based on an incredibly biased framework of sensory perception and mental processing that was developed to survive a hunter-gatherer lifestyle on the African savannah.

Did you know that to show submission to the leader of their pack, chimpanzees will come before him and bow to show their respect? That blew my mind because humans have been bowing to their leaders since... since we had leaders! And we can invent all kinds of justifications for it. He's descended from the gods, he led our armies to victory over the foreign barbarians, I agree with his views on tax policy... but at the end of the day, we're just apes bowing before another ape who groomed us well enough to become the pack leader.

How you can trace the whole path of your life to some small, seemingly inconsequential event.

Decades ago, when I was new to this area, I met a guy on the golf course and we became friends. I met others through him, and now 90% of my friends and contacts can be traced back to that meeting. If I had not golfed that day, or got one extra red light on the way to the course, would I have a whole separate set of friends now?

The fact that I will never know how things turn out. What becomes of the world once I'm gone? I only understand life as the version I've lived. I never get to know the future.

Similarly, you'll never truly know what happened in the past.

How much quicker time goes by as you get older. Remember when you were five, and a summer vacation felt like a whole lifetime?

I just wanna be a kid again.

This is the one that gets me. Sometimes I look at someone and I just come to the realization that they are having thoughts exactly like me and thoughts I could never have. It just trips me out.

Knowledge lost.

Societies that existed millennia before ours had incredibly complex social structures, massive infrastructure, built incredible wonders, understood boggling amounts of modern math and did it all in harsher conditions with less technology.

So clearly they were smart and capable, at least some.

Imagine all the great knowledge that they had which we lost. All the theorems or observations they made in societies that lasted ten times as long as many of today's, which disappeared in war or accident.

Knowledge defines man; we are a species of filers, who wish to make a pattern and sense out of chaos. Yet knowledge is so very fragile.

Not only is knowledge fragile, but in some cases, it may even be unobtainable.

In a trillion years or so, the expansion of the universe will progress to the point where it becomes physically impossible to detect the light from other galaxies. So much of what we know about the history of the universe has come as the result of studying other galaxies, and once they finally disappear beyond the cosmic horizon, all of the insights they carry with them will vanish forever. If any civilization is just emerging at that time, they'll have no way to know that the universe is expanding, or what it was like in the past. They will be completely isolated on a single galactic island, with no hint that a much larger reality lies beyond what they can see. Although they may think they understand the universe they see around them, they'll never truly have a complete picture.

Because we can see this inevitable loss of information coming, it forces us to ask an incredibly uncomfortable question: has fundamental information about the nature of our universe already been lost beyond some unknown cosmic horizon? Could it be that we are fundamentally wrong in our understanding of reality because an important piece of the puzzle has been lost and will never return?

That every public institution, every province of government, every law of any nation...it all works because a sufficiently high percentage of people silently assent that it does. It doesn't matter what type of government is in place; if 70% of the population woke up tomorrow and decided that currency has no value and governance is unnecessary, that's exactly what would happen.

Pick a random day on this planet 1 billion years from now. Barren. Baking in the light of an expanding red giant we once called the Sun. None of us here and no trace that we ever were here. All of us lost to time. Our Earth just another void celestial object.

That no matter how much you get to know someone, no matter how much you share your life, learn about them, feel as though you are almost the same person, there will always be an infinite gulf between who you think they are, and who they really are.

You cannot know someone else. You can only know your perception of them. Your experience of that person flows through the filter of your personality, your experiences, and memories, your biases and intuitions. You don't know them, you know your conception of them. The subjectivity of experience makes truly knowing another person completely impossible.

We are all perfectly isolated souls, completely separate from everyone else, desperately reaching out to convince ourselves we aren't really alone.

In 125 years, there will be an entirely new set of people on this planet.