Yet another quantum mechanics joke
(Because I don't have time to write about what I really wanted to mention today, I'll have to fall back on another quantum mechanics joke, this time almost disguised as a story from my college days.)
I hadn't seen my girlfriend in a few weeks because of Christmas vacation, and when I finally saw her again, she looked different in some way.
"You look great," I said. "Have you lost weight?"
"No," she said.
"Are you sure?" I said.
"Positive," she said. "I know exactly how much I weigh…"
And she disappeared.