Civilization is related to People. you are likely to find People in/at/on Supermarket. you are likely to find Money in/at/on Supermarket. 
Custom is a type of Practice. Custom is related to Usual. Usual is similar to Regular. 
Civilization <--RelatedTo--> People --AtLocation--> Supermarket <--AtLocation-- Money 
Practice <--IsA-- Custom <--RelatedTo--> Usual <--SimilarTo--> Regular 