You may believe that a line should be formed to enter the subway car or that other passengers should not stand so close to you. Those beliefs are intangible because they do not have physical properties and can be touched.
One norm I learned is waiting in line and waiting for my turn. I think this is a folkway because it is an expected everyday behavior. I learned this by watching other people and from school and family. If someone cuts in front of the line, I may feel uncomfortable or think it is rude. Other people may also complain or ask them to go to the back of the line. This is an informal negative sanction.