Common Sense?

So, what is common sense? I might not be able to define it, but I can sure say it is lacking the majority of the time. Do we each define common sense by placing the invisible bar on par with our own level of thinking? In doing this do we elevate ourselves above the rest of society by mentally placing our intellectual standards on others? I think that common sense is simply another way to say, "Thats obvious to me". Too often we use the mindframe of "common sense"ing those around us to discriminate others. Far too often I see people lacking "common sense", but is that simply me subconsciously saying they are inferior? What do you think?....