Bingley states that Darcy is very fastidious (excessively particular; hard to please) when Darcy displays this trait in his refusal to dance with Lizzy: At such an assembly as this it would be insupportable. Your sisters are engaged, and there is not another woman in the room whom it would not be a punishment to me to stand up with" (ch. 3).

And as Mandy points out, Darcy doesn't bother to lower his voice, though he knows Lizzy is nearby, when he makes that insulting comment about her appearance.

Yes, "it is difficult to be in a situation where you don't have much in common with others around you" (quoting Tiffany Lynn), but Darcy doesn't just "hide in the background"; he makes it clear that he refuses to mix with the Meryton people because they are inferior to him. To me, this isn't an indication that he can't mix with them because they won't have anything to talk about; it's an indication that he indeed thinks himself above his company, and will not be bothered make an effort (or pretend) to be courteous.