The Model: Why get to Action line if all we want to do is Feel a certain way?

As Brooke says, the only reason we ever do anything is because how we think it’ll make us feel, and I agree. But if this is true, why continue to the Action Line in the model/life? Why not just change our thinking and therefore our feelings and never get to the actions and results/external changes? Trying to reconcile this psychology/philosophy in how we live.