Things have limits. Oh yes. But these limits are defined not by a little single point, but more by volume, and they are, in the end, pinned down by their relationships. Eventually, just the relationships based on particles which collide with one, then the other.
Indeed, a photon trail of reflected light is, in fact, a relationship between all the things struck, and from the photon's point of view time is stopped, and happens all at once (at least, that is the mathematical statement in Einstein's theories. So in a way, if only poetically, the photon strikes all the objects simultaneously, and connects them in spacetime.
And my point? These relationships are how one gets some readings on things. How we make a measurment. Relativity and skepticism are not about denying things exist (!) or that they can be compared. They are an explanation of in what sense and by what means things can be said to exist, and in relativity is a statement that not only can things be compared but that's all you can do, the thing in itself is considered a thing in relation.
When using relative means to figure people, it is pretty hard, impossible, to peg a person, which means to visualize and understand the limits to their volume and thereby their potential. You can limit a person in your mind, but in reality, your estimate is wrong to some degree, and in humans, it can be a huge and unlimited degree of error, because people do change.
As do relationships.