Okay let's start with what the debt ceiling is. You and your wife decide to go to Costco, but beforehand, you agree not to spend more than $100. You can see where this is going, right? So, you go to Costco by all of the things on your shopping list, which totals just under $100. You then see [fill in the blank.] It's going to put you well over your pre agreed upon amount. Of course, you get it anyways. You just went over you and your wife's debt ceiling.
That ceiling is an artificial, agreed upon limit not to spend more than a certain amount. Of course, if you and your wife had agreed not to use more than $100 in electricity at the beginning of the month, and then went over it, you once again blew through your debt ceiling. You're still going to have to pay that electric bill, though. If you don't, then your lights are going to get turned out. In the case of the US budget, though, the United States has plenty of credit, and we'll simply get hit with some late fees or higher interest rates. Now if the US were to decide not to pay its obligations at all, or only in part, then **** is going to hit the fan.
Paying your debts is different from the debt ceiling. The debt ceiling itself may be moot since, you may have heard people calling for Biden to invoke the 14th Amendment, which reads:
The validity of the public debt of the United States, authorized by law, including debts incurred for payment of pensions and bounties for services in suppressing insurrection or rebellion, shall not be questioned.
This could be read as requiring that the US government pay its debt. It has not yet been put to the test.