"Do something but you don't know why you want to do it?"
Usually the desire to do something is sufficient reason for me to do it, unless there are better reasons not to. So I don't often wonder about why I have those desires. But looking back at things I've done, it's not too hard for me to rationalize to what I think is a decent degree of accuracy why I did them. The better you understand how your mind works, the better you are at deciphering your own actions and reactions. I don't think it is possible for there to be a human that never forms an erroneous conclusion about something they've thought, felt, or done. But the more self-aware you are, the less you make those errors.