I have been playing and moderating D&D for a few years now, and
have compiled extensive notes on the wildly divergent personality types
that play D&D. The first thing my notes revealed to me is that the wildly
divergent personalities can be grouped together into several different
main types:

The poor loser: The poor loser often gets killed in the early going
and always lets everyone know his/her displeasure about it. The poor
losers are also further divided into 2 groups: the quiet and the loud.
The quiet poor loser will usually pout for the remainder of the adventure,
while giving subtle hints of his displeasure — like feeding your cat to your
brand new trash-masher. The loud poor loser is much more vocal, while
being less subtle. He will often, after getting a bad break, call everyone
fools for attending your adventure and saying that you’re out to get him. I
have one piece of advice for inviting poor losers: don’t.

The doomsday predictor: This guy is a real pest but he really
doesn’t mean to be. He wouldn’t be that bad, either, but he lowers the
party morale <l=d107>  and takes the fun out of playing. If I had one of these in my
group I would either 1)Don’t invite them 2)Talk to them before the
adventure and snap them out of it 3)Try not to kill them too often (but be
careful not to let them take advantage of you).

The masochist: This guy is fun at first, but gets to be really boring
after a while. The sight of a player jumping into a Gelatinous Cube or
attacking a Balrog with an unlit torch is funny the first time, but can get
boring (really boring) after the third or fourth time. I really don’t care,
however, as their characters have short life spans and so never gain
powerful positions in the group.

The smug player: This is the player type that I can’t stand. When
you kill 1 of their characters they say something like “I didn’t like him
anyway” and are always smug. These guys always have a whole catalog of
smug/smart answers, suitable for any occasion. I usually kill them off at
low levels so they don’t attain positions of power in the party.

The genius: The genius delights in thinking of ways to outwit you
and can usually quote al1 3 D&D booklets; plus the supplements,
forward and backward — without looking at them once. But I have
nothing against them and I delight in thinking of ways to outwit them,
although it can become tiring after a while.

The real-lifer: The real-lifer acts like he really was his character and
takes everything on the level. The real lifers are usually good players but
can get easily depressed, especially when a character of theirs is killed.

Shy people: Believe it or not, shy people do play D&D. They are
fine players but tend to let their characters be controlled by more
dominant players (like me) and can have less fun than the other players. I
like to let shy people get high level characters and often appoint them
group spokesman — which usually brings them out of their shell.

The dominant player: The dominant player is often a fine player
but can tend to TAKE CONTROL over the group and spoil everyone else’s Time.
The solution to this is not to appoint them group spokesman, as they
would like to be.

I have left out many types, in the interest of space, including the
average D&D player (if there is one). I did this because all other player
types are just a form of one of these.

I also have some more advice for the moderator, however: never lose
your temper — it just worsens things — give subtle hints of your
displeasure instead. Always keep your dice rolls secret and roll the dice
often, even if not needed, to keep the players guessing what you’re rolling
for (and to prevent them from knowing when you are rolling for
wandering monsters, traps, and secret doors).

Sorry for the humor! 
A BIG thanks to Mike Carr for what he wrote on June 2, 1978, from memory. 
See page 2 of your PLAYERS HANDBOOK. Thanks Mike!