Yes, competition can be both, positive and negative. I very much see it the same, when there are "losers and winners". Depends on the field of resonance when a game was won by one kid or one team and how the others react to that winning. If the "losers" are sad, mad and disappointed and appear hostile to the winners team, the winners lose, too. Feeling joy about having beaten another one is very different from the feeling of having succeeded in something for the self.