If you think about it, much of what people do is guided directly or indirectly by a drive to attract a mate. A person who is accomplished in some way is more desirable than someone who is not, and this competition can drive the will to advance technology, create music and art, and to organize larger social structures. This is why a failure to attract a mate usually leads to depression and lack of motivation. This may also be why people with higher sex drives tend to be more successful (e.g., as inventors, artists, politicians); the two drives go hand in hand.