A robot may not injure a human being or, through inaction, allow a human being to come to harm.
A robot must obey the orders given to it by human beings, except where such orders would conflict with the First Law.
A robot must protect its own existence as long as such protection does not conflict with the First or Second Laws.
Isaac Asimov was one of the great sci-fi writers of the 20th century. So naturally, at the dawn of the space age, the military wanted to tap his brain. In 1959 he was approached by ARPA (now known as DARPA) to "think outside of the box" about how ideas are formed. His brief work for the organization has never been published, until today.
Probably more inhibiting than anything else is a feeling of responsibility. The great ideas of the ages have come from people who weren’t paid to have great ideas, but were paid to be teachers or patent clerks or petty officials, or were not paid at all. The great ideas came as side issues.