Science knows a lot, we've explored the furthest reaches of our solar system, reached the tops of the highest mountains and probed the deep oceans, but it doesn't know everything and there is still at least one mystery that we're still unravelling: It's you.
Or more accurately, it's everyone (although you are a special little snowflake, don't worry).
Considering we spend our entire lives staring out from inside a warm, squishy human body, you'd think we'd have got a pretty good handle on it, but unfortunately this just isn't the case.
Despite the fact that we have made some incredible strides in our understanding of ourselves, like, we've managed to sequence the human genome and can grow kidneys in a lab, there are still some frustratingly simple questions about us that science so far hasn't been able to answer.
Why do we kiss? What is that little jerk for when you're falling asleep? And what exactly is the matter with teenagers?
These, and many more, are the questions that scientists are still asking about the human body and we're definitely closing in on the answers.
Although we should probably just accept the fact that we're never going to understand teenagers - not that they would want us to anyway.
10. Hypnic Jerk
You fall into bed after a long hard day of adulting, you're just dropping off to sleep until OH GOD PANIC you feel as though you're falling off a cliff and you jerk awake.
This is what is known as a Hypnic Jerk.
There are a couple of theories around the cause of this phenomenon, but no one can seem to agree. The main one - and the one that most often gets repeated knowingly by people in pubs - is that it's a vestige of when human ancestors used to sleep in trees. The hypnic jerk is supposedly a reflex that stops us nodding off and falling off our perch.
They usually occur when a person is falling asleep when they're not completely relaxed, or when they didn't mean to, and this lends credence to the idea that it would serve as a little "are you sure you want to do this?" reminder before you enter the land of nod.
Another theory is that it has something to do with your brain not quite nailing the transition between its sleeping and waking states. When we're asleep, our brain temporarily paralyses our body, this means that you don't get up and act out even your most vivid dreams, but this paralysis can panic the waking brain, this often manifests are a night terror.
It is thought that if the brain gets the whole falling asleep and temporary paralysis thing the wrong way round, it can trick it into thinking that something is terribly wrong, causing it to jerk violently to be sure you haven't actually lost the use of your limbs.
It's also a great way of making your boss completely aware of the fact that you've just dozed off in a meeting. Again.