Thinking about different languages in the terms of "useful" or "useless" according to the number of speakers they have.
Edit: What I mean specifically is not for someone to want or not to personally learn a language, but if the existance in itself of a language is more or less valuable according to how many people speak it (per example and as I explained below, believing that Occitan's existance is useless because there's already French to talk to Occitan people with, who already understand it). Yes, this happens.