The United States did away with debtors' prisons a long time ago. So the short answer to your question is, no, you will not go to prison if you fail to pay your credit card bill.
If you stop making your car payments, your vehicle will eventually get repossessed. This will involve a repossession agent employed by your lender coming to your home, hooking your car up to a tow truck and taking it away.
Military personnel, veterans, and their families are often the targets of aggressive or unscrupulous debt collectors. Now that the Consumer Financial Protection Bureau is keeping statistics, it's possible to quantify a degree to which abusive debt collectors target service members in Ohio and elsewhere around the country.