My High-School English teacher was well known for being a fair, but hard, grader.

One day I received a B minus on a theme paper.  In hopes of bettering my grade and in the spirit of the valentine season,  I sent her an extravagant heart-shaped box of chocolates with the pre-printed inscription: "Be Mine."

The following day, I received in return a valentine from the teacher.  It read: "Thank you, but it's still Be Mine-Us."