According to Freud, the reality principle in the mind, playing out likely scenarios, weighs the costs and benefits of any effort before deciding either to act upon and gratify or else to restrain and abandon an impulse arising in accordance with the pleasure principle. And this interplay of pleasure principle checked by reality principle is obviously fundamental to all motivation and values, being crucial because happiness comes in meeting ones needs for capable interaction with responsible others, partaking together in that very interplay of pleasure and reality principles that imbues living with meaningful relevance and autonomy.