To understand time is to attempt to understand the infinite. There are infinite universes and all are subject to time in some fashion It is the absolute of existence.
Time is relative. As a child it drags. As an adult you find yourself outpaced by time’s passage. Time refuses to move at all when you are bored and disappears when you are occupied. It is we who define time. We measure its passage. We define a day by the movement of our planet and our sun. Yet day does not start when the sun reaches an arbitrary point on the horizon. It starts when you wake. What matters the time that passes when you are not conscious of its passage? Does the time you spent doing something trivial count against you in a way that spending time profitably does not? Is time a bag of coins you take to the fair? Does someone judge which items took your fancy over those that would have been a wiser choice?
Time continues even when you are not paying attention of course. It is implacable. We age. We grow from pouchlings to children to adults and then wither away to wizened oldsters. Yet time did not note your passing through its existence. To time we are nothing. It is we, the finite, that consider time and its passage through our lives.