Check out this video that you will surely relate to! This is an excerpt from a training based on the book "Understanding Poverty" by Dr. Ruby Payne. This highlights the fact that there are hidden rules in society. Dr. Payne talks at length about how schools are typically run on "middle-class" rules. If you have students being raised in poverty, or conversely, in wealth, these students are not being taught the same rules at home.
"A 'hidden rule' is a method of interacting that is common to agroup of people (subculture). Every subculture or class has "hidden rules", but not even the class members realize the rules are there. But when someone violates the rules, it sets up a barrier. Know the "hidden rules" and you will be able to more effectively cross cultural lines."