The reason for this is that it's the room where people most frequently put on makeup, apply ointments and bandages, tweeze eyebrows, and do all sorts of other things that require adequate light.
On prom day, tweeze strays early in the morning, ice any redness away and use a brow gel (if your brows are unruly) to keep them in place.
In between visits, tweeze the stray hair.
However, pulling hair out at the root may actually result in thicker faster growing hair, so avoid the urge to tweeze unwanted hairs.
The most common place to tweeze is on the face, either to remove stray hairs from the chin or upper lip or to shape eyebrows.