polite banana

The last banana in a bunch, the one that is almost alway over ripe before anyone gets to it.

The over ripeness of the banana causes a rash of politeness in people...

Jane: Can I offer you this last banana?
John: No, it is ok, you can have it.
Jane: No...I must insist, you have it...
John: No really...it is your banana, you have it...

(This demonstrates how the last banana in the bunch can become a polite banana...no matter what state of brown it is in)