How someone handles winning and losing reveals so much about their character. The earlier kids are taught this, the more prepared they will be for the real world (which includes plenty of both).
In his essay “On Anger,” Seneca lays out some specific advice for fathers when it comes to teaching kids how to be good sports. He writes: In contests with his comrades we ought not to allow him to become sulky or fly into a passion: let us see that he be on friendly terms with those whom he contends with, so that in the struggle itself he may learn to wish not to hurt his antagonist but to conquer him: Whenever he has gained the day or done something praiseworthy, we should allow him to enjoy his victory, but not to rush into transports of delight: for joy leads to exultation, and exultation leads to swaggering and excessive self-esteem.
This is important. We want our kids to possess the will to win, but not so much that it possesses them. We want them to feel good when they win, without being so dependent or addicted to that feeling that they are crushed when, inevitably, they lose. We don’t want their success to fuel their ego, or their shortcomings on the field to lead to insecurity or self-loathing.
It is, like all things, about balance. And most of all, about being respectful, being responsible, and enjoying the process more than the results.