Its not will power, its obedience!

When I have an app tell me to fast, why is easier? Its not as energy draining?  
We are programmed to be obedient, being hierarchical species. It is natural for most of us to obey than to disobey?  It really takes a lot of energy to disobey, thats why we are so angry when someone tell us to do something we don't want to do. Because our minds feel compelled to do it and we have to fight that instint to not do!
 Back seat driving for example, its dangerous because of the high possibility of the driver following the suggestion in spite of it being dangerous, like turn left when a vehicle is coming from behind. We find it very hard to not do what the person is casually telling. It takes lot of mindfulness to not take the suggestion . Thats why we said look what u made me do! and we are NOT playing the blame game. We are telling the truth. 
Even when the order is what we want to do we find it annoying , because it makes us lesser in the hierarchy? but that another discussion.
I am thinking there may be a practical advantage to this obedience. When we try to fast - we are using will power to stick to it. Its is hard and draining until it becomes a habit. But when we are using a fasting app? When the app tells us its Time to fast - Its not using our limited will power which is kind of draining to use but we are using our less draining but natural instinct of obedience? Thats why it is lot easier from the beginning?