Non self-evident

I would like to ask why we have to get sick to understand how health is not a natural condition. Only then we realize how lucky we have been until then, or how important it is. I wonder why we can not appreciate what we have all the time, and not only when we do not have it anymore. Sometimes, we even challenge our bodies, or we look at danger with disregard. 

A wise chinese friend once told me, you only know how much something or someone matters to you, when you do not have it anymore. For people, is then normally very difficult to have them back. In general anyway, it is difficult to appreciate what you have and we always look towards what we do not have, in a constant research of improvement. The funny part is, sometimes this constant stress toward something else does not let us realize that sometimes we already have what we are searching for, or, it makes us sick, so that finally we have to stop and look only around our bed, or inside us.