Clean jokes-Signing a cheque

Louise went into her bank to cash a cheque. She looked so hesitant that the cashier went to help her. 'Please sign the back of the cheque, 'the teller told her, 'as you'd sign a letter.'
Louise looked extremely grateful, scribbled on the cheque and passed it back to the cashier.
Signed on the back was: 'Yours affectionately, Louise.'