They are restless; they are easily bored, they want to solve problems and not interested in pleasing their bosses or are led by them. They resent bureaucratic bottlenecks that slow or delay them from achieving their results. Skilled and talented people know that you as an employer cannot go without them.
They know how much their skills are worth in the market; because they are members of their professional bodies that supply them with market information for their skills. They cannot be fooled too with fancy titles and positions that do not come with attractive remuneration packages.