"I'm a Mog: half man, half dog. I'm my own best friend!"
-- John Candy in "Spaceballs"
Human nature is such that we look for categories and labels by which we can recognize and identify ourselves and each other. It starts with infants learning to discern "self" from "non-self" and adds layers from there. Even Koko the gorilla (trained in a form of American Sign Language) was able to identify herself as "Koko fine gorilla."
I think that if we didn't have words and terms for these things, we would still make intuitive distinctions based on our feelings and self-perceptions, compared to our perceptions of where others are coming from.