I've seen very much characters by people, who love making ineffective characters in name of "roleplaying".
In reality, however, they are more often disruptive to dm and insist on other players following their lead too. It's ok, if you want to play "adventures of ordenary slightly unusual people", but really bothersome, if you try to play heroic fantasy.
Another trend is to do characters, that no way are likely to ever go into adventure in the first place, at least not with people they are supposed to be travelling with (aka rest of the party).
Some things picked by these players are illogical even from point of characters, considering what kind of life these character are supposed to have lived.
And in game where dm likes making opponents challeging, delibrely bad picks for character's abilites forces dm to make enemies weaker, making encounter also appear somewhat less, than it's supposed to feel like.
This behavior is really hard to alter, since it is easier to tell 'no' to somebody abusing rules, or 'no' to someone min-maxing just for the heck of it, than to one of these 'elitist role-players'.
Of course, not everyone I've met makes ineffective characters on purpose. Sometimes they just didn't realize they would be ineffective, or dm failed to tell what type of game he/she intended to run.
Mmh, I can see making weak characters for challege, if games I have played had been more like "Ancient Domains of Mystery" or "Nethack", or whatever roguelike, especially if I'd already tested all the killer-combos of min-maxing.
