 What do Miss Drayson and Kylen Braynek have in common?
Every man in the Diplomatic Corps who developed a twitch or a quirk was shipped to Saarkkad IV to work under Bertrand Malloy, Permanent Terran Ambassador to His Utter Munificence, the Occeq of Saarkkad. Number two suffered from some sort of emotional block that left him continually on the horns of one dilemma or another. No two men were alike, and yet there sometimes seemed to be an eternal sameness about all men. And he had his memories of Diane, dead these ten years, but still beautiful and alive in his recollections. To violate the rigid social setup of Saarkkad would mean the instant closing off of the supply of biochemical products that the Saarkkadic laboratories produced from native plants and animals—products that were vitally necessary to Earth's war, and which could be duplicated nowhere else in the known universe. Not the worst ones, of course; there were places in the galaxy that were less important than Saarkkad to the war effort. It had taken Malloy a long time to get it into Miss Drayson's head that it was perfectly all right—even desirable—for her to keep secrets from everyone except Malloy. She came in through the door, a rather handsome woman in her middle thirties, clutching a sheaf of papers in her right hand as though someone might at any instant snatch it from her before she could turn it over to Malloy. Miss Drayson stood there calmly, her face a mask; her emotions were a secret.
 They are both paranoid about what other people think.
 They externalize a lot of their thought processes.  They are constantly processing extreme amounts of details.  They both dislike interacting with other people.  They are both paranoid about what other people think.