Helpdeskpilot

The Rules of pushing in soccer seem to be a rule of using totally referee discretion. Can anyone tell me what the exact definition of pushing is? I realize that you can make room for yourself but it seems to me that the rule need further defining. I asked a ref at a soccer league game today why it was not being called. He stated that it "wasn't pushing". I respectfully disagreed, well ok maybe I wasn't the most respectful but to me pushing is pushing. I know the ref so I want to be able to apologize if indeed I was in the wrong. It seems to me that in a game of younger players this is going to result in more pushing as they are just "getting even" and probably will lead to an all out "push fest". Please help. The most complete answer will get the 10 points.