Why does it matter?

You ask someone if they know a certain person.  They say, "yes, the name. Describe them." How do you respond?

Age. Gender. Height. Weight. Skin color. Hair color. Eye color. Everyone is labeled in each of these categories, and it's how most people describe each other.  But why is this stuff the most important? Using this to describe someone doesn't really narrow down who it could be - millions of people could have the same combinations of this description.  What really separates us from each other is our personalities and actions.  Unless someone doesn't know who a person is by your physical description, you would describe their personality or an action they're known for (and most often negatively).  Maybe you say someone is a teenage female, 5' 6", thin, white, with brown hair and blue eyes.  That description would fit many high school girls, so it's not until you describe someone as obnoxious or quiet, or athletic or humanitarian, that it starts to make major differentiations.

So why do we start with something that isn't effective? Why do physical attributes matter in descriptions, when personality and actions are what really differentiate people?