Seeing animals engaging in the often quite elaborate performances of mating behaviour, and considering that this is not modeled by imitation but somehow innately programmed or 'instinctive' behaviour, we tend to downplay the role of desire-pleasure, as we understand it, in non-human creatures. That is, the term desire refers to something almost rational, as if it is the expression of the ideal-motive to maximise satisfaction. If you could ask a dog why it was fucking what would it answer? Most likely 'I don't know I have to do this' - its face expresses less happiness than it does when getting a belly rub, or playing. For us 'I do it because it feels good' requires no further justification, and the vicissitudes of human desire arise from the lived elusiveness of the triggers for satisfaction. It is therefore redundant to say that you are programmed to seek satisfaction, no, rather satisfaction is what it is you seek, and so even if it looks to someone on the outside that what you are aiming at is anything but satisfying, that is only because the true satisfaction is unconscious, or concealed even from yourself. In some cases it might be a memory of a past state of fulfillment. So that would imply that you evaluate your present state as unstably unsatisfying and so you naturally try to bring about a situation analogous to the one you remember in which you felt so much better. Thus you have a sort of constantly active internal meter of satisfaction, generally hovering somewhere in the middle of its range, and a radar which detects prospects for change in satisfaction in your immediate environment, and a continuously evolving situation map, and you try steer a course that brings positive changes closer and keeps negative changes further away. Experience renders the cues hopelessly complicated so that much of the human drama concerns the misadventures of a subject in search of satisfaction, especially in its sublated form as 'happiness'. This is necessarily a rough sketch but what it is aiming at is the peculiar ontological status of satisfaction as the unitary principle underlying the confusion of motives and objects. What is it that you are trying to bring about, what is the substance of satisfaction, this irreducible sense of being more real, more complete, of not needing?