Optical illusion

I began to look thinner in the mirror. I told myself I shouldn’t worry, but that just gave me two things to hate myself for. The next week I saw my reflection’s fingernails: smooth, unbitten. Manicured? He began dressing better than me, and his wrist grew a big silver watch that needed winding. I couldn’t look him in the eye any more: he was so much taller, just from standing straight, I wound up looking up his nose. So I stopped looking altogether. A few weeks later I came face to face with him in a lift. He was thinner than ever, and slumped, and ragged, and his eyes stared blankly ahead. I reached out to touch him, and felt cold, smooth glass.