Debt is a promise. A promise you make is based on expectations about the future, including promises that others have made to you. The more promises we make to each other, the more likely we are to be in a chain where somebody cannot keep their promise, which means that we are vulnerable to a cascade of failed promises. When such promises pervade the economy, once we see that they have been broken, we have to reorganize ourselves. This happens by closing businesses, by liquidating assets, switching jobs and eating cat food because the pension is now worthless.

In financial terms, such cascades are typically mopped up by central banks through dilution of the money supply and/or taxpayer financed bailouts.

Long story short: more debt means more risk of a financial crisis.

p.s. I think it is not helpful to use terms such as "our own", "ourselves" when trying to understand these issues.