In theory we have the possibility of doing anything (of course there are some physical restrictions). The only wrong thing you can do is not to exert your freedom.
But this freedom generates anxiety. Martin Heidegger stated that humans are nothing: we are just possibilities waiting to be materialized through our actions and decisions. The problem comes when we realize there's nothing to guide us. "Is this decision the right one? Where will this take me? What would have happened if I had taken another path?" These thoughts often appear. Also, we will die someday, thus "becoming nothing" is another possibility. Our lives are just different ways of reaching our deaths.
Heidegger also said that when we approach the world, we always have a certain state of mind or mood. We are not apathetic. This affects our perception of the world and how we interact with it.
The world is how we perceive it. It's up to us to make the most out of it. We are rationally aware of this. Then why can't we put this into practice all the time? Because of our irrationality. Our fears and insecurities get in the way. This issue will be discussed on my following posts.