Your mood is a liar. You made the plan when you were smart. You made the plan when you were clear-headed and calm and could see the whole board. The version of you that made the plan had context. The version of you that wakes up groggy at 6am and doesn't want to do it has almost none.
You are not going to out-discipline a bad environment. Nobody does. The people who look disciplined mostly just built a world where the easy path and the good path are the same path.