That requires thinking in “negative space,” doesn’t it? It specifically refers to people we don’t think about. You might start with people who aren’t like you, and people you don’t have to deal with in your everyday life. What might make you a little afraid to speak to someone, let alone touch them or sit next to them on a bus or in the library? Maybe someone really old and not very clean. Maybe someone talking to themself, or lying on the ground in public, or wearing winter clothes in the summer.
now your problem is going to be trying to think why that kind of person is in that kind of situation!