The paper focuses on the concept of implicit rules as discussed in the book by Jaroslav Peregrin Člověk a pravidla (2011). It aims to point out deficiencies of the concept of implicit rules through an analysis of examples of its application, mainly of what it means to follow and interpret an implicit rule. It is argued there is no test to decide whether we follow or interpret implicit rules correctly. Another problematic aspect is that the relation between normative practices and rules is not as straightforward as suggested by Peregrin, but it is much more various.