‘Laws’ of Software Development
Careful with Postel's Law: it brought us a lot the mess we have with web standards.Quoting wikipedia https://en.wikipedia.org/wiki/Robustness_principle:> 
In RFC 3117, Marshall Rose characterized several deployment problems when applying Postel's principle in the design of a new application protocol.[3] For example, a defective implementation that sends non-conforming messages might be used only with implementations that tolerate those deviations from the specification until, possibly several years later, it is connected with a less tolerant application that rejects its messages. In such a situation, identifying the problem is often difficult, and deploying a solution can be costly. Rose therefore recommended "explicit consistency checks in a protocol ... even if they impose implementation overhead".