Rules are super great, we all need them weather we want them or not, however, dont feel that these "rules cant be surpassed in any way. Thats when you start to deprive your mind and your body of the freedoms it should have. Self discipline should always be balanced with a healthy amount of do-what-you-want- today because you deserve it after sticking to your guns for so long!
I think we can all agree that Americans seldom know what exactly portion control is (thank you McDonalds). For someone trying to get to a goal physical level, however, they should keep in mind that 50% of reaching physical goals is effort, the other 50% is in what your fueling your body with, in the right amounts, at the proper time.