Or they have different length?
Not all people speak the same language nor they do not have the same color and here you see that "difference" is a natural thing, so why should we be upset?
We will never upset about a person who see a white car as a black even the car is white in reality as it is observed by he majority of people, also this person may say there nothing called real according to him/her, again it's up to him/her but they should force the majority to agree with their opinion.