It is important to have your own characteristics since we have over 6.7 billion people, it'll be hard to talk or call someone specifically. As you start to identify someone more thoroughly, you start to talk about their physical appearance. Tall or short, fat or skinny could be used to identify, although it depends on each and one of us's own perception on others, but most the the time, we do agree with each other. To go into more dept, mental factors, which are usually told by your close friends, or your family, because usually you can't tell much about a person if you do not know a lot about them. Mental or social factors are usually the hardest to tell without knowing someone. You wouldn't know how to tell a person's personality, how nice or how evil someone really is, and still everyone thinks differently, you might disagree with someone else who thinks someone is good or evil.
Physical, mental, and social factors are not the only factors to identify a person. It could be anything. You may say someone who likes a brand, wears some unique clothing, a fan of a music band or even someone who doesn't like anything to identify an individual. All and all identity is what makes you yourself, what others say you are and who you really are. What others say about your identity might not always be true, you know yourself.
