no fool like an old fool, there's - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
An old fool is the worst kind of fool, as in He's marrying a woman fifty years his junior—there's no fool like an old fool. This adage, now considered somewhat offensive for stereotyping old people, appeared in John Heywood's 1546 proverb collection and has been repeated ever since.