Mac hates his first name. If someone else had it, he wouldn’t have a problem with it. But it’s his, and it fits wrong. He doesn’t know what he’d change it to but something less masculine. He decides that from now on he will only be referred to by surname. He introduces himself as Mac, and that’s much more comfortable. It’s not quite a perfect solution, but mostly it works.
Doctor Macartney has an excellent ring to it. At the age of fifteen he’s figured out that hearing people call him Mister makes him cringe, and that Doctor seems like a reasonable compromise. Picking his O Levels, he decides on mostly sciences, and works hard to get into medical school. Six years of training and hard work to never be called Mister again. It’s worth it. When people ask why he wants to be a doctor (his parents, school friends, teachers) he tells them he wants to help people. It’s true, but not his biggest motivator.
At uni, away from his parents, Mac lets his hair grow. He tells his flatmate, one Guy Secretan, that he can’t afford it. And Guy accepts this; Mac didn’t go to public school, doesn’t have rich parents, and is currently working as well as studying. Guy has got an impressive allowance from his father, and has money to burn, the finances of his flatmate baffle him. Mac could easily get a haircut. If he was really desperate, he could cut his hair himself, or get Guy to cut it for him. But he doesn’t want to, he likes having long hair. A privilege he never had at home, through a combination of strict parents and school administration who cared more about enforcing uniform policies than dealing with bullying.
Holly is wonderful. Mac can honestly see himself spending the rest of his life with her. Except for one thing. It’s not the fact that he would quite like to be a dad one day, and she doesn’t want kids, it’s that she insists on calling him Paul. He doesn’t have the words to tell her why he hates this nickname, so he tries something else. He calls her John. She thinks it’s cute, and keeps calling him Paul. he puts up with this, but it chips away at him. Six years later, they have their final argument. He could tell her that he hates being called Paul, but it’s really irrelevant. He can’t explain why her calling him Paul hurts so much.
When Caroline drunkenly tells him that she kissed Sue White, Mac’s heart leaps. He has no idea why. There is absolutely no reason why finding out the woman he possibly fancies snogged another woman should make him so happy but it does. After he gets home and sobers up, he examines the feeling. It’s not jealousy. It’s something like relief. Because Mac knows that something isn’t right about him. He doesn’t have a first name, he shies away from most masculine things, including being referred to as sir or mister, but doesn’t actually want to physically change any part of him. Knowing Caroline is a bit lesbian, 5%, makes him feel more secure in fancying her. Makes him think there could be a future.