The adults appear to have a mental illness, and a poor attention span, as they cannot stop chatting about soccer, airplanes, mountains, money, and the local burglar without crying a river, run back into their house, pee over the carpet, and still welcome their guests in to their kitchen, where a thriving colony of roaches and ants are having a squaredance in tile:#3457.
Sometimes the children are smarter and more active than their parents, keeping their fun, comfort, and social levels up, while somehow attaining a genetic trait that grants them immortality. However, if they ever miss a single bus when the time arrives, a humvee arrives to take them to military school.
Often its funnier to make the lives of your "victims" as agonizing as possible, rather than making them successful and prominent members of Simian society.
Ah the joys of The Sims!