When I was a child up until about fourteen or so, I handled losses very badly. No always losing once, but definitely if I lost two or three times in a row. I would become terribly flustered and hostile, usually cursed, growled, stomped, and was likely to drive people away from playing the game. Throwing and object wasn't out of the question either.
Today, I still have a competitive streak that I try to keep subdued, because I think it's a very unhealthy thing. Losing still makes me upset, actually, but I turn it all inwards now. When I lose, I'm disapponted in myself. That's always been the problem, regardless of how I show it.
Sounds like me about a decade ago, in all honesty it wasn't so much the losing the bothered me, I'll even throw a game to cheer up or boost confidence in someone who isn't doing so well. It was the reaction to winning from the other side that made me become hostile and sort of throw a temper tantrum in my own way.
When someone is up in your face going "hooyaeh biiiatch, taste your defeat muahahahaha" and stuff like that, that's what pisses me off, still does.
So if you're an ungracious sore winner, then expect me to the perfect ungracious sore loser in return.
As a child I was very bad. As you grow older, however, you learn that being upset that you lost won't solve anything. So I learned to find the fun side in losing What I find trouble not getting frustrated at, is people gloating that they won, especially in games etc that involve a lot of luck.