Player A and player B are all in. Player B has player A covered. Both players turn over whatever - pick any two hands. Cards are tabled and chips are in the pot, with the flop to come.

The type of game and limits are irrelevant.

Before the flop comes, player C says to player A "I folded the same thing." Player A then gets upset -literally mad - with player C for saying that he folded some of A's outs.

Is there something I missed regarding not disclosing what you may have folded when two players are all in? How does that possibly effect the action? Other than knowing that you may have less outs at the start of the hand, why would anyone get upset at GAINING information about their hand in that situation? The info may suck, but still....

Was it said in a way that A may have interpreted the statement as "You fool, why would you play that? I folded the same rags"

I have seen this happen many times and it used to bother me (a long time ago). For someone that doesn't know the game well, I think it eliminates some of the excitement from the gamble.

In essence, the person is being told they have less of a chance to win than they thought.

It's the same as getting pocket J's and someone flips up a J when folding. People get upset even before putting money in the pot. When I point out that it was valuable extra information for them, the typical reply is something like: "yea, I know" (grumble).

Commiserate with them, they are good or the game.

You dashed his hopes and humiliated him at the same time.

Nah, the statement was made matter of factly. There was no malice present when the statement was made.

While any reasonable person shouldn't get mad about this, I still think its best to not say anything. Lets say the situation is AK vs a pair and we folded an ace. Maybe the guy with the AK thinks its bad luck or something that you said that. The guy with the pair will now feel more unlucky if he losses the flip. Its one of those things were it really doesn't benefit anyone and just give an excuse for someone to be upset.

If Player C isn't in the hand, he/she should probably keep his mouth shut.

I'd guess Player A was behind and irked some of their outs were now in the muck.

This. Poker is an emotional game. Unless you are deliberately trying to needle or put someone on tilt just don't say anything when you are not in the hand.

This happens all the time. OK, not literally, but in the late stages of tournaments when there's a lot of all-in hands, it's definitely not rare. I've seen people interested and indifferent to the information, but never seen anyone mad.

I consider it normal discussion, and wouldn't let one crazy guy's reaction stop you from talking in the future.

If someone is steaming and is all in, even saying 'Nice weather' could set them off. Read the situation. Most of the times, it isn't a problem, but if a guy is in a volatile mood, don't talk to him about anything, least of all his hand or your cards.