If I borrow ten bucks from my friend to buy a pizza, I feel pretty bad if I haven't paid him back in awhile. I can't even imagine what it would be like to owe people 14 billion dollars. That's crazy!
Here are a couple videos to help you understand the situation. The first video is a helpful visualization of how big a trillion dollars actually is. The second video is a CNN Student News clip explaining what the debt ceiling is.