"You're not the center of the universe" is a pointless phrase. Everyone sees the universe from their personal perspective, and thus everyone is the center of their own universe. People can try on other people's shoes, but in the end your own pair is always your favorite, amirite?

Super-over-analytical

I think you misunderstood the phrase : /

Technically you are wrong since the universe is not infinitely large.
But in terms of just meaning "you're not the most important person in the world" you're also wrong. Whether or not you like it a world leader is more important than just one citizen.