"Time flies..." is what is known as a proverb, and a proverb is defined as "a condensed but memorable saying embodying some important fact of experience that is taken as true by many people." Most people think of this particular expression as a truism, I know that I do.
NPR's All Things Considered had a story about a researcher at University of St. Thomas in Minneapolis who studied whether "changing" time had any effect on the participants' perception of the task as being fun. It seems that it did! Those who were tricked into believing that time had flown by, perceived a task as being more fun. It remains to be seen if the research has any practical application, but, anything that makes a tedious or unpleasant task seem like fun might be worth pursuing!
James Gleick has written a book called Faster: The Acceleration of Just About Everything [529 GLE]. Gleick says,
We humans have chosen speed and we thrive on it--more than we generally admit. Our ability to work fast and play fast gives us power. It thrills us.With the new year upon us, I wonder what Father Time thinks about all this business about perception of time?