“Manipulative” people are ones who lie or imply their motives for doing something are other than what they are. It’s not effective to be manipulative. Manipulation only “works” to the degree that your victim is not paying attention. Yet think about this. The purpose of manipulating someone is to gain something from them. Yet you’re counting on this person’s weakness — i.e. inattention, lack of focus, lack of reasoning — in order for your manipulative strategy to work. Manipulation will not work with the most attentive and competent of people, the ones with the most to offer. Manipulation will work with those who are torpid, mentally lazy or irrational. But so what? They don’t have that much to offer. This is why manipulative behavior is not “selfish” or self-interested. It’s simply foolish.