My main problem with Mensans is that it seems some (too many) of them seem to think that because they are smart, they don’t have to think. For example, we have a guy where I work who has “Mensa” in his license plate and is active in the group. But what an idiot he is! He believes in all sorts of nonsense, but has nothing intelligent to say about it. He is one of the laziest buggers around. If he thinks he’s right, that’s it. Doesn’t matter if you prove him wrong; he won’t change what he’s doing. I’ve reviewed some of his work and pointed out to his supervisor (he’s in another section) how he was in error and what would happen. His response was to ignore it, wait 'til the deadline when this had to be done, and submit it as he had originally done it, leaving his supervisor no time to have it redone the proper way. I know for a fact he has done this several times with other people as well. And I also know of other Mensans who act in a similar manner to this guy, though it would probably be overgeneralizing to assign too much weight to the group based on the actions of these folks.
I am eligible to become a member of Mensa, but I’m just too cheap to pony up the dues for meetings that I’m too busy to attend just so I can say that I am a member.
I spend some of my time poking around the various Mensa newsgroups. Some of the people are nice. But, others, holy mackerel. God should be as perfect as those people. They know EVERYTHING. It really turns me off to the idea of ever joining. If it weren’t for the fact that I’m not like that (at least I HOPE I’m not) and most of you aren’t like that, I would think that high IQ causes some kind of brain degenerative disease that causes you to become a pompous ass.
Come to think of it, since I found the SDMB, I haven’t been back to the Mensa groups. I prefer the lively exchange of ideas that goes on here to a bunch of people competing to be the smartest of the smart (here you’re just trying for the smartest of the smartasses - but that’s different :)).