Far be it from me to claim your experiences are false -- your experiences are your experiences.
I never claimed otherwise...
But in my experience, the greatest indicator for how well a character would jibe with a group is how good the player is--and secondarilly, how compatabible the character is with the player's abilities and preferences. Everything else is secondary to that.
It is hard to disagree with you there... My experience, though, is that some people will play stupid character in a way that will ruin everyone else fun. Other play them as forgetfull, clueless ones, without trying to ruin the scenario, nor the other players fun. I guess you would call them good players, and then we would agree.
A dumb character can get in the way of others roleplaying--playing the character as a useless bore. Or they can sit back and let the smart people decide what to do. Or they can make a funny comment or two and then let people get on with it...and then make a "dumb" comment that actually turns the entire conversation on its head. Good players (or players having good days) will choose better options here; worse players will choose worse ones.
I may be a little too demanding, but I think a good player is someone that will enhance the experience of other people with his roleplay : players and gamemaster alike.
Moreover, what I like with Dungeons & Dragons 4 is that all player characters are involved.
In combat, a "dumb" character could set his head on fire or move quasi-randomly -- or they could suddenly become a tactical genius -- or they could act out of character motivations and capabilities, using simple and practiced tactics, but avoiding novel tactics unless pointed out by someone else (thus allowing other players playing smarter characters to shine).
Would you still play with someone that insists on playing stupidly on each and every combat ? How long would such a character last ? How long would your character last with such a stupid character on your side ? How the gamemaster would feel when the stupid guy is acting in a way that makes each encounter a deadly one, when it should be a challenging one ?
I guess your answer is that a player that ruins the game because he insists on playing in a way that ruins everyone else fun is a bad one... My point is that it is very easy to do that with a stupid character, and it is even easier to justify ruining the fun all around.
In puzzles? Well, see above; the same options more or less apply.
I try to put my puzzle inside a skill challenge of sorts. I also try to build them in character. Every player should put all efforts to play this kind of scene as any other kind of scene, especially in D&D4, where all is done to involve everyone.
Some memorable stupid characters:
In a theater style larp, Arabian Nights, a player was playing an ogre. The ogre was converted to Islam by a sage, but being an ogre, he got a few things wrong. So he started going around demanding that people "worship floor!". Eventually, someone figured out what was going on and explained he needed to say worship -on- the floor. (of course, this was a storytelling rpg more than an adventuring rpg--but D&D isn't limited to only pure adventuring either!)
It is not a stupid character. It is a clueless one. A real stupid one would have insisted in keeping telling people to worship floor. In fact, this is not the kind of behaviour I pointed out.
As you surely guessed, the behaviour I dislike is people insisting on playing stupid people stupidly, even at the expense of other players and gamemaster alike.
In a parody run through the Grimhawk Dungeons of Doom (and with the option to give everyone 9 lives), I decided to play a paladin with a miniscule Int. And lots of courage. I charged everything, failed to learn from experience, and set off many, many traps (usually only endangering myself). It was fun for everyone--if anything the over-careful wizard was the real downer in the that game. Despite my best efforts, I even survived the adventure (with one life left).
In a parody, such a behaviour is "in character".
And...frankly, all decent roleplay efforts involve playing your character "a little bit stupid." Your character isn't you, and doesn't have your experiences and perception. So at some point, it's good to hit a point where you realize what the "right" thing to do there is...and then decide that, for one reason or another, your character isn't going to do that; they're going to do what they think is the right thing, regardless of the flaws you see in it. Even Sherlock Holmes is going to underestimate (most) women--despite otherwise being brilliant.
I could not agree more. It is always a good idea to spice up any kind of character with a little bit a "dumbness" or "cleverness".
The problem I have with stupid characters is that most people I met (who instist on playing them) play them dumbly in a selfish way, and justify their (bad) attitude by pointing at the Intelligence score on the character sheet.
Sure it is nice to have some flaws in a character, they enhance the experience. But they should never get in the way of other players and gamemaster fun. With a stupid characer it is much too easy to cross this line... At least, this is my experience.
I guess that most of my players play dumbly from time to time, and so do I (both as player or gamemaster). The "good" player would (role)play in character (dumbly at times) without interfering in a bad way with the fun of everyone else. So this behaviour goes unnoticed by me. Therefore, I only remember the bad behaviours.
Your labelling of players in "good" or "bad" player maybe the best one.