Human enhancement always sounds good on paper, but if you look at how enhancement techniques are actually being used, you may be excused for having doubts about the whole enterprise. Just take the neurotransmitter oxytocin, which has been celebrated as a wonder drug, a "cuddle hormone" and "love hormone". It is supposed to enhance our social competence, to make us nicer and more considerate, more attentive to the needs of others, generally more trusting and at the same time more self-confident. It even increases the sexual drive in men.
I think the example shows very nicely how on the one hand the enhanced human may become more capable of manipulating the world around him (including other people), but on the other also more prone to be manipulated by others. It seems that the more extensive the control we gain, the more extensive is also the control that we may be subjected to.