Like I said previously, my former roomate is in Mensa. He was definately the type to brag about it. One time we got into an arguement about how a database table should be laid out, which he knew nothing about, but he decided to say "2%!" I was ready to punch him.
My sister is also in Mensa, she's always been one to be better than everyone else at everything.
Finally, I was watching People's Court one day, and this woman who was the plaintiff decided for whatever reason to tell the room "I'm in Mensa, I know what I'm talking about!" She lost the case hardcore, for being stupid.
In conclusion, Mensa dont mean sh!t other than giving people that look down on you, another reason to look down on you.