Man who stopped line of tanks

Today's video showed a video of a man laying down his life in order to do stop the tanks, he probably believed they're shouldn't be war. He stood in front of those tanks in Tienanmen square, his identity is still unknown. I'm not sure what I would die for, there isn't much that I would die for. I guess if I had a family I would die for them, but I don't at the moment so I'm not sure if there is anything I would die for. I mean I think I would like my chance to experience life before it's over and it's like I didn't even exist. We say we would die for things, but if we were faced with that choice and had to make a decision in seconds, would we really lay down our lives? Is it really normally to have to spend hours upon hours deciding to lay down your life for something you already said you would die for? If you say you would die for something, and you had to die for them, then why would you not be able to do it in a matter of seconds, with barely any thought?