Feng shui is about the Qi气（energy) flow, if the qi flows correctly then the feng shui is good, if the qi flows in a messy or disharmonious way the feng shui is bad. Qi exists everywhere, therefore feng shui is all areas of our life. Qi can be redirected to harmonise with the environment by physical input.
Here is a real life example: there was a cross road near where I lived, with “Give Way” lines on each road. The traffic was busy, the qi flow was straight and strong. Each time I passed that intersection I was extra careful, for it was a major accident point. One day I noticed a roundabout had been built in the middle of the intersection, like the one shown opposite. The cross road formation was broken by the roundabout, the qi flow was harmonized, and every passing car followed in order. Since then accidents have been rare.