A watched pot never boils
Time feels longer when you're waiting for something to happen.
'A watched pot never boils' is one of the homely and improving proverbs that is ascribed to Poor Richard, which was the pseudonym that Benjamin Franklin used when publishing his widely popular annual almanac. Franklin, a tireless and industrious polymath, was fixated on such improving aphorisms and published numerous of such in the guise of Poor Richard between 1732 and 1758. The general theme of the proverbs, which include:
There are no gains without pains.
Early to bed and early to rise makes a man healthy, wealthy and wise.
Plough deep while sluggards sleep and you shall have corn to sell and to keep.
Have you something to do tomorrow? Do it today.
can be summed up as 'Industry: good; sloth: bad'.
Amongst many other callings, Franklin was a noted diplomat and during his time as American minister to Paris he was directed by the King of France to write a report on Franz Mesmer's controversial theory of 'animal magnetism'. In the report, published in 1785, Franklin included this text:
Finally another Breakfast is ordered. One Servant runs for fresh Water, another for Coals. The Bellows are plied with a will. I was very Hungry; it was so late; "a watched pot is slow to boil," as Poor Richard says.
Actually, Franklin ought to have written "as Poor Richard might have said", as the proverb isn't found in any of the Poor Richard almanacs. That's a moot point however, Franklin and Poor Richard being one and the same.
Of course, Franklin was also a celebrated scientist and would have been aware that watching a pot has no effect on how long it takes to boil. Like many of the most effective proverbs, this one is poetic rather than literal.