Most (if not all) western people would describe a single major chord as happy and a minor one as sad. But I've heard that this is very subjective thing and that in some cultures these associations don't apply per se. So you could say, music sounds happy/sad because you believe it does.
Is it possible to deliberately change the emotional response you get when you hear different chords? I know that in a chord progression context you can make certain chords give a different feel than they normally would. But I mean on a more fundamental level.