Have you ever had someone ask you what was wrong with you? I'm sure you have, whether you'll admit it or not. I know it has happened to me a many number of times. For a long time I was not be able to come up with a generally good response to that question, but now I think I've come across the solution.
Make a list. It's actually quite simple. Just make a list of all the things that are "wrong" with you, the more nonsensical the better. You should keep it with you at all times, possibly in your wallet or purse.
The look on people's faces when you actually pull out a list is priceless, even more so once you proceed to name each item on it. I have attempted this a total of four time on unique people and have received some fairly hilarious responses. Most people have a puzzled look and just are speechless.
P.S. Remember to add the fact that you carry the list around with you as an item on your list.