I want opinions in this one. This stuff has been bothering me for a month now. Everything you'll see below is of course, fictitious. Let's say everyone is born immortal. Obviously we don't know about it so we won't care and do stuff that we want, when we want. The truth is that something makes us mortal. In your opinion, what could the "thing" be? Don't take facts in mind because this is just a question to know other people's opinions. So don't go like "but the blabla theory states that blabla hush hush kukakuka ".