The most realistic scariest thing I believe in is the United States will be hit with a nuclear bomb. I hope this doesn't happen obviously, but unfortunately I do think we are going to get hit by one in our lifetime. I don't know which country or terrorist group would do it, but I feel it is the inevitable. There is no way these countries are spending billions of dollars and putting this much time and effort just for fun.
You haven't been living very long on this planet, have you?
If you demand respect or gratitude for your volunteer work, you're doing volunteering wrong.