A column in the New York Times mentioned some of the health benefits of having plants and flowers in indoor environments. As long as you are not allergic, plants and flowers help foster a more positive and upbeat mood. If you are allergic, maybe cacti, which do flower beautifully on a sunny windowsill, could be a reasonable option if sanctioned by your allergist. Also the Zyrtec website has a page on healthy houseplants for people with allergies.
See also my blog on combating Winter Blues Seasonal Affective Disorder-S.A.D.), here: http://www.drmarionrollings.com/combating-autumn-and-winter-blues-seasonal-affective-disorder-s-a-d
Here is the New York Times article: http://well.blogs.nytimes.com/2015/11/20/ask-well-do-indoor-plants-improve-our-health/?em_pos=small&emc=edit_hh_20151125&nl=health&nl_art=6&nlid=65386032&ref=headline&te=1
And here is the Zyrtec page: https://www.zyrtec.com/living-with-allergies/gardening/allergy-friendly-house-plants