Yup, astroace is correct that plants help improve the chi that gets into the bathroom. As its in the Northwest sector it affects the Helpful Friends and Mentors aspect. As long as no one is having major problems with regards to those then don't worry too much about it
In feng shui as well as basic etiquette, the bathroom reflects how the occupants really are. A dirty bathroom means the inhabitants lack focus, are negative, etc. Its the first room I always ask and inspect when I go either to an office or home.