People get caught up on debt as a number, because it seems big in relation to money that most people deal with.
So "oooh scary number 17 trillion dollars think of the children ooohhh" its not bad. It's like borrowing money to buy something that makes you money. Who cares what the payment is, as long as it brings in MORE money than you pay out. So you buy infrastructure and help poor and, well, for the americans, you buy a shit load of military stuff. BUT...you can move people and goods, and not trip over dead poor people and you keep your industry in business and take all the underprivileged kids out of their neighborhoods and educate them, and occasionally some of them don't come home.
So its measured against GDP-Gross Domestic Product.
For the US? U.S. National Debt Clock : Real Time
Everything you need.
It's hovering, according to that at about 100%, meaning all the economy in a year could wipe the debt. Canada is 64%. Ireland is 1000%, and they are still going.
These numbers don't include unfunded liabilities which is the sum total of every dollar they as a country have agreed to pay, but haven't actually found the money to do. That's about 60 trillion. Why do people care?
It never seems to go down. The closest in recent times is Clinton, and even he swapped deficit money for more unfunded liabilities to do it.
The interest payments get higher to service the debt. That's a more important number as you have to deny your citizens use of their money in terms of paying out interest on money used for foregone expenses. Why people shouldn't care
Ultimately, the best is to at least have a balanced budget, and only go into deficit during times of economic distress(much like Canada did). The US is the reserve currency, in the largest economy in the world by far. They kind of don't need to play by the same rules, as they just...don't. Create a war, and their economy prospers. Create peace...and their economy prospers. Buy some gasoline, and chances are...their economy prospers.