Effectively, the Sims themselves are the Feng Shui analyzers, in the way that the layout and open spaces of their house and the objects in it affects the routing efficiency and creates flows and bottlenecks, which affects how much time they have for other more productive uses of time than walking across the house to the bathroom, queuing to walk through doors, navigating through crowds, which indirectly affects their overall happiness and other motives scores.

To show how happy your Sims are, the antlers of the Beaver Pelt Moosehead occasionally moves up and down to reflect the overall happiness of the family members!

http://sims.wikia.com/wiki/Beaver_Pelt_Moosehead

If your Sims get really depressed, and have a Tragic Clown Painting on the wall, a real Tragic Clown arrives and performs annoying tricks that make you even more depressed, and he is very difficult to get rid of.

http://sims.wikia.com/wiki/Tragic_Clown