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.