I think the tricky part is with how we manage our expectations about the kind of goal we have in mind when we start a project. If I have a goal to “buy groceries from the local store”, I do not need to also spell out the implicit subtasks, such as “pick up your wallet”, “take your keys”, “make sure everything is okay at home”, “wear your shoes”, “buy 5 tomatoes and 10 onions”, and so on. When we estimate our ability to finalise a project, we make self-evaluations both for the subtasks and for the whole project.