Most games require a central conflict to work. Although winning is not the only reason we play games, the vast majority of games do end up with a winner.
Many games take the requirement for a conflict and apply it directly, turning the conflict into a contest of martial skill. Diplomacy and Risk are the two best known examples, and Chess is a more abstract form of this kind of conflict.
Other games provide the conflict in other arenas, Monopoly’s property development, Acquire’s company building or Puerto Rico’s shipping of goods.
Few games have no conflict in them, you should always look for a conflict when designing a game, or a good reason to not require one. Find out what resources the game cares about, make sure they are scarce, and make sure that they can change hands among the players. This should drive the conflict, and with a good conflict, you can create a good game.