The Sims is a life simulation game where the player creates virtual people who live in a real life like sandbox world. There are no major goals to the game other than the users own personal prerogatives.
Pro The game offers real-world reasons that can motivate the player, but doesn't force them
Making sure the Sims are fed, happy, live in nice houses and are generally well off are all easily relatable things to anyone and don't need to be expressly stated for the player to want to improve conditions for his protagonists. At the same time, the game doesn't force anyone to make sure the sims have great conditions. The game allows exploring how different choices affect the outcome of the situation.