How can we teach that to our budding chess-players? With role models I guess. That's why there are the senior sections in each tournament where the games are often the last to finish. The lower tables of the junior section are often the first to finish.
There should be someone t to explain the purpose of playing in a tournament. Tournaments are definitely not social in nature. Every competitor strives to win. However, some will take it lightly while others see it as the game of their life. Chess players should treat tournaments somewhere in between - be serious but then its not the end of the world. A loss merely means something's gone wrong and it is important to address it to fix the problem.
Yet I often see children playing with portable game-stations, game cards or playing on their parents' mobile phones in between games. Isn't this wrong? If they wish to play chess in a friendly or cordial environment, then they should do that in chess clubs, or play online without having to compete. If there are lessons to be learnt, it should be learnt there and then after the game - the player should reflect on what happened. However, the game is usually not recorded and the player forgets what had happened. So it is theoretical possible to lose the same game in exactly the same way AGAIN. I have seen it happen and often wondered if it's not a waste of everyone's time to be there for the tournament if we keep repeating our mistakes??
So parents should help set priorities straight for their children. Go to a tournament by all means to learn, to experiment, to understand what needs to be done for the next. Don't go to a tournament to snack or socialise to a point where the result doesn't matter. There are better ways to do that like going for a picnic in the parks or beach. Trivialising the competition isn't going to help them later in life when everything important seems like a comedic movie to them - to enjoy and forget.