In fact, he has never been entirely sure what beings mean when they speak of friendship. Love, hate, joy, anger — even when he can feel the energy of these emotions in others, they translate in his perception to other kinds of feelings.
The kinds that make sense.
Jealousy he understands, and possessiveness: he is fierce when any being encroaches on what is rightfully his.
Intolerance, at the intractibility of the universe, and at the undisciplined lives of its inhabitants: this is his normal state.
Spite is a recreation: he takes considerable pleasure from the suffering of his enemies.
Pride is a virtue in an aristocrat, and indignation his inalienable right: when any dare to impugn his integrity, his honor, or his rightful place atop the natural hierarchy of authority.
And moral outrage makes perfect sense to him: when the incorrigibly untidy affairs of ordinary beings refuse to conform to the plainly obvious structure of How Society Ought To Be.
He is entirely incapable of caring what any given creature might feel for him. He cares only what that creature might do for him. Or to him.
Very possibly, he is what he is because other beings just aren't very... interesting.
Or even, in a sense, entirely real.
—
Star Wars: Revenge of the Sith novelization, from a passage beginning with "This is Dooku, Darth Tyranus, Count of Serenno:"