There are several reasons why a fastener may become extremely tight. It could be due to a manufacturing defect, over-tightening, or even corrosion. When this happens, it can be extremely difficult to loosen the fastener using traditional methods. It is important to use the correct tool for the job in these situations. The tool you use will depend on the size and location of the fastener. For example, if the fastener is located in a hard-to-reach spot, you may need to use a long-handled wrench.