Technical Debt works in a similar way to financial debt - when you take shortcuts to roll out a product on time, you basically take on debt. The symptom is the more debt you take on, the more it slows you down, and the more you will have to take on in the upcoming stages of the project.
If you don’t pay it off before moving on to the next stages of the product, your work will become a lot harder, and you’ll likely be forced to take on even more debt as you move forward.
When taking short cuts and delivering code that is not quite right for the programming task of the moment, the symptom is that a development team incurs Technical Debt. This debt decreases productivity. This loss of productivity is the interest of the Technical Debt.