Teammates that are emotionally secure are not jealous of how a win makes another teammate look. They are free to cheer a teammate on without feeling like they are seen as less than. There is nothing more encouraging than to be honored by a teammate. On the flip side, there are few things that can cause a bigger buzzkill than a teammate that cannot genuinely congratulate you on a victory because they feel inferior. Great teams cheer each other on. Ordinary teams struggle with egos.