One interpretation might be -
The financial "facts of life" may be that you can't spend more than you earn.
Some people ignore this. They think they can just keep on borrowing, and spending, and running up debt.
For them, the "financial facts of life" is a difficult lesson to learn.
It is difficult to get them to understand and live by the basic rule of personal finance: if you didn't earn it you can't spend it.
- For Teachers