“A watched pot never boils”

“A watched pot never boils” (also “a watched kettle never boils” and “a watched pot is slow to boil”) means that constant anticipation and watching makes things seem to take longer. When a pot isn’t constantly watched, it often appears to boil quicker.
 
The phrase “a watched pot is slow to boil” has been attributed to Benjamin Franklin, circa 1778. “A watched pot never boils” is cited in print by 1808.
 
 
Bartleby.com
A watched pot never boils
Something we wait for with impatient attention seems to take forever.
The New Dictionary of Cultural Literacy, Third Edition. Edited by E.D. Hirsch, Jr., Joseph F. Kett, and James Trefil. Copyright © 2002 by Houghton Mifflin Company.
 
The Yale Book of Quotations
Edited by Fred R. Shapiro
New Haven, CT: Yale University Press
2006
Pg. 622 (Proverbs):
“A watched pot never boils.”
Elizabeth Gaskell, Mary Barton (1848). “Watched milk never boils” appears in Charles Dibdin, Jr., The Wild Man (1833).
 
(Oxford English Dictionary)
a watched pot never boils and variants: time feels longer when you’re waiting for something to happen.
c1778 B. FRANKLIN Paris vii. 926 Another Breakfast is ordered… I was very Hungry; it was so late; ‘a watched pot is slow to boil,’ as Poor Richard says.
1848 E. C. GASKELL Mary Barton II. xiv. 184 What’s the use of watching? A watched pot never boils.
1880 M. E. BRADDON Cloven Foot xxxviii, Don’t you know that vulgar old proverb that says that ‘a watched pot never boils’?
1940 C. BOOTHE Europe in Spring x, ‘He [sc. Mussolini] is waiting to see how the next battle turns out,’ they said… ‘A watched pot never boils,’ they saidonly this one finally did.
2005 Chicago Tribune (Nexis) 25 Apr. 1 It was like the watched pot that never boils. You were waiting and waiting for them to do something right.
 
Google Books
16 July 1808, Cobbett’s Weekly Political Register, pg. 77:
...I am thoroughly convinced, that, as a “watched pot never boils,” so, a watched penny never breeds.
   
Google Books
2 December 1828, The Kaleidoscope, pg. 179:
...chatting and joking with him took our attention off the saucepan, and as sure as “a watched pot never boils,” our unwatched pot boiled “in no time.”
     
Google Books
Peabody’s Parlour Journal
Published by Peabody & Co., 1834
Item notes: v. 1-2
Pg. 92:
... which clinging, however, does little more than sharpen his appetite, and double his faith, in the old adage, that a “watched pot never boils.”
   
24 October 1840, Polynesian (HI), pg. 77:
It has been said that a watched pot never boils; but despite that saying, our pot did boil, notwithstanding it was watched with an intensity of interest, by those whose lives might and probably would have depended upon the success of the experiment.