Technically, gray (or 'grey' if you are in any English speaking country in the world except the U.S.), is really not a color. It is a neutral, in the same category as black and white. While white is the combination of all the colors, and black the absence of color, gray is considered to be achromatic.
Maybe tired is gray.
Surely all the dust of a whole year of lessons learned and work completed is gray.
When all the brightness of bulletin boards and posters and calendars and bins and tubs and the stuff of my world is put away, then the place seems to fade to a soft, sad, sullen, empty gray.
And the long, seemingly endless hours and minutes dripping off the face of my classroom clock, trudge one behind the other, clad in dull, deadening working man's gray.
Next week, after some much needed rest, I will sit here in my quiet home, and come once again to appreciate the grays of a summer thunder storm, the soft gray fur of the household cat people, the misty grays of my summer dreams, the silver in his hair -- and mine... I will open my eyes and the world will glisten in its pewter toned, dew-covered richness, and I will be able to rejoice.