I've never committed meta in public before. Hmmm. And of course I'd pick not the shattering scene but the funny scene. Spoilers only for "Heart." Anyway, the Paper, Rock, and Scissors from "Heart" is obviously supposed to be a little bit of comic relief, and judging by the ep reactions I read, it worked. Even simply as comic relief, though, it does more work than that, being comic relief we don't know we're going to need until the end of the ep. But I think there's more to it than that.
(Let me just say that it is a brilliantly humorous bit. These two badass guys play a children's game with serious "game faces" - Dean's "stick it to ya" face in particular when he throws was killing me. As does his frustrated grunt/"God!" when he loses again.)
Sam mocks Dean for consistently picking the same option - "Dean, always with the scissors." What both of them ignore - or perhaps just don't realize - is that Sam necessarily picks the same option all of the time too (rock, to crush the scissors). Which, fine, Sam likes to win and either Dean hasn't caught on or holds on to hope that one glorious day Sam will throw paper and scissors will reign supreme. But getting back to the nearly inevitable outcome of the game - Dean stays consistent. He fills a role, just as he does throughout their lives. Dean is always the good son, good brother, good soldier. Whatever Sam does, however he behaves, is always - given the nature of family dynamics, sibling dynamics in particular - going to be read in reaction to that. Sam can fall in line (be just like Dean) or he can rebel (be unlike Dean). Of course Sam is a good son, good brother, and good soldier. But read in tandem with Dean, he comes up short, at least in his own estimation. Being the younger sibling means that Sam always has to consider Dean's actions before taking his own, just as he does playing PRS.
There's a whole other meta somewhere in there about Dean's steadiness providing the comfort zone for Sam to play - Sam can form outside relationships, can study hard, can go off to Stanford because Dean's unswerving commitment to family has given him the freedom to explore all of these options - but I think that's too much for me.
So, what do you think? Also, I'm a little curious about how everyone played this game. We hid our fists behind our backs and chanted, "Paper, rock, and scissors, SHOOT!" and on "shoot" we brought our hands to the front. And I have a feeling Sam would be in for a rude awakening if he ever competed in the World Championships - unless he used his special powers.