Or your car blows a gasket. Then you have desires. All humans do, some more than others. You may desire all of it all at once. Occasionally you cannot control yourself and one of your desires is filled.
Debt makes up the difference between income and expense.
Debt itself is not bad. The problem arises when debt accumulates for no apparent reason. Problems and desires would push your credit card balance upward each month because there is no other place for the money to come from. There is no mention of a savings program. Nor a retirement plan.