Oxymoron - Two meaningful words put together that completely ruin the English language yet still get the meaning across.
I can usually come up with a few good examples but nothing comes to mind. I guess that "Common Sense" is the biggest one. Observing the general population one notices a lack of sense, therefore it could not be considered as being common.
Take this morning for example. It was raining quite heavily and I could barely make out a few buildings in the city as I was crossing the Narrows Bridge. In other words, visibility was minimal. Some idiot behind me, in a grey car, was driving without his lights on. Not much sense there. A few minutes later some idiot in a two-lane street decides to drive straight across the road, across the footpath, and into a parking spot. It is still raining heavily, you are only allowed to cross one lane at a time, he didn't have time to do a proper shoulder check (as he was crossing from the righthand lane) and how was the traffic supposed to stop in the wet if he had misjudged his sudden change in direction? Bit of sense lacking there also.
I must do a search for this elusive item known as common sense. It must be an intriguing beast. Join me in my search.