The first time a four-minute mile (running a mile in under four minutes) was achieved was in 1954 at Oxford by Roger Bannister. Until that point, it was considered to be a near-impossible feat to accomplish.

However, just two months after Roger Bannister first accomplished it, it was done twice more in Vancouver. This time, John Landy joined Bannister in the accomplishment. And since then, it has been accomplished a few more times.

When something has never been done, there is a mental limit that we place on the act. But once we have seen that someone has done it, we now know that it is possible. It then gives us a lot more confidence to push ourselves to actually do it.

A similar story plays out in Harry Potter and the Prisoner of Azkaban, where Harry manages to conjure his most powerful patronus to save Sirius. He manages to do it, having never succeeded at it before, because he knew he had already done it (in the time warp of that story).

While this is true on the positive side, it is also true on the negative side.

As James Clear puts it so well, "Every action you take is a vote for the type of person you wish to become."

Achieving the impossible across all of us is one thing. What's more common is to move in the direction of what we thought was impossible for us as individuals, by taking little steps.

Opting for a bowl of fruit instead of that bag of fried potatoes, or opting to write for an hour a day rather than spend that time scrolling through our social feeds, are all little decisions we make and little actions we take everyday. And by taking these actions, we are defining the kind of people we wish to become.

We don't become drastically different people overnight. But every action we take compounds over time.

Facebook's ten year challenge, that seems to be the rage on the Internet at the moment, is focusing on the visual change in us.

But, when I look back at all the actions I have taken over the ten year period, I can see that each action has indeed been a vote for the person that I've become today.

Who do you want to vote for over the next ten years?