- Wear and tear: Friction can cause surfaces to wear out over time, as the constant rubbing of two surfaces against each other can scrape away material. This can be a problem for machinery and other moving parts, as it can lead to reduced efficiency and even breakdowns.

- Generation of heat: Friction can also generate heat, as the energy lost to friction is converted into thermal energy. This can be a problem for brakes, as the heat generated by friction can cause the brakes to fade and become less effective.