Feelings and thoughts do not define who we are; they are just part of the weather of our inner world.
The average person might articulate them differently, but we all think about interpersonal relationships in one way or another. Writers just express that in different ways and capture it in different ways. To some degree, we're all thinking about the same things. It's the zeitgeist. The trick, in a way, as a writer, is to hope that your interests in some sense link up with the culture around you.