Embellishment

I'm a sucker for passementerie -- the definition of which, according to Wikipedia, is:

"the art of making elaborate trimmings or edgings (in French, passements) of applied braid, gold or silver cord, embroidery, colored silk, or beads for clothing or furnishings. Styles of passementerie include the tassel, fringes (applied, as opposed to integral), ornamental cords, galloons, pompons, rosettes, and gimps as other forms. Tassels, pompons, and rosettes are point ornaments, and the others are linear ornaments."

Besides, a good sized tassel makes sure the tiny key to the secretary doesn't go missing!