What are the most important design patterns that software engineers should know to work at Google, Amazon and Facebook?

The emphasis on memorizing design patterns as fixed rules is misguided; they are actually observations and common solutions that help create a shared vocabulary among developers. Skilled software engineers should focus on deeply understanding the reasoning behind these patterns, so they can apply or adapt solutions independently rather than forcing problems into rigid patterns. Over-reliance on design patterns often leads to overly complex and poorly maintainable code, which is not typical of top-tier companies like Google, Amazon, or Facebook. Ultimately, adaptability and critical thinking are more valuable than simply knowing specific design patterns.