Competitive nature is something that in some ways is trained into you. I do think that there are some people who are simply just more competitive by nature. You can prove this by seeing two children from the same parents, one being ruthless in trying to win at every sport, the other not seeming to care at all whether they win or lose.
At the same time, you can also see a family is, in general, more competitive than the average family, and this seems to be a direct result of parent sibling relationships.
One of the reasons I have always loved organized game nights is that it brings people together. Even though most people who know me would probably say that I like them because I’m competitive and love to play and try to win (which is part of it) but it gives a natural avenue to get to meet and know people without having to make up conversation. You see them and their interesting quirks naturally as you play the game.
I’ve also realized that, whereas a party that is open to do anything and talk about whatever may intrigue a social butterfly, someone who struggles to meet people and ask questions may have more trouble and may not enjoy it as much. By having organized games, you can allow those who are not as outgoing to have something to do in order for them to then meet people. Especially if you play team games where the participants are required to work together.
There’s a fine line of course. If you do too much organization, the free spirits of the group will feel constrained and not enjoy it nearly as much. Organization, but not overbearing organization I believe is the way to make almost any party successful.