Sometimes, days are too dragging for us that we have to live through them. Say, a day on which you have to take an exam through the day.
But then, there are times when days pass off very quickly – say on your date. Days and weeks fly off past you and you won’t even mind it.
So, I think, time is the theme of the sentence; and how important and unimportant are the ways in which we represent time like days or weeks.
Student or Learner