Alive yet dead

Why would someone want to die? I mean, why this desire? We're all going to die anyway. Why wish for something you know is going to happen eventually, sooner or later, one way or another? Why not instead wish to live? Why would one wish for something he knows nothing about? Death is one of those very few things mankind will never truly understand. You want your life to come to an end but you have no clue what is coming afterwards. One who is continuously wishing death on himself isn't particularly living. You've never tried living yet you want your life to come to an end. And you've never experienced death yet eagerly want to. How very messed up is that?
Since you've never experienced any of them, why not try to experience a decent life first? Living won't harm you as others have tried it, however death might as you don't even know what to expect.