I once asked my dad what was the greatest invention ever made. He gave me a really simple answer. He said he thinks the greatest invention is glasses, because without them, people with eyesight problem wont be able to see anything, thus making them unable to invent anything even if they wanted to.
Recently, I think the GPS can be one of the greatest invention ever made. I know it was used by the military or NASA long time ago but I don't think I'll be able to live without it. My faithful Garmin Trucker GPS. I'm serious. I go everywhere with it and I know I wont ever get lost without it. It certainly doesn't help being a girl and living alone in a foreign city but I need to go to places to buy stuff or visit people. I seriously don't know how people survive before mapquest, google map or the GPS.
I remember my dad getting lost a lot. But then that was fun because all I needed to do was sleep behind the car. =)