Last night, as we were sitting down to my very favorite tacos in the whole wide world (at La Taqueria on Mission at 25th, make sure to order the carne asada with cheese), I heard Marco gasp. Something about the small sitting-twisting motion of sliding onto the stool had triggered old injuries, and just like that, his back was thrown.

On the half-block walk to the car, Marco was a sad, slow-moving hunch of a thing. “Wow,” I said to him, “You went in all young and strapping, and you left an old, old man.”

Marco, in an elderly mutter: “Stupid Dorian Gray tacos.”