Mommy and Our Piano Tuner, to Use a Hypothetical Example

Father to little daughter: You are the most beautiful girl in this photo... and I'm not biased.
(daughter smiles)
Father: Do you know what "biased" means?
Daughter (rolling her eyes): Yes, it means that you like both boys and girls.

--F Train

Source:
http://overheardinnewyork.com/