We're told in life to stop and smell the roses, or other similar idioms. Giving ourselves time to unwind, take in our surroundings, to pay attention to the finer things in life.
It's the same in videogames, that sometimes if we're so hell-bent on rushing to that end goal that we pass by some interesting finds. It may be that the world needs saving, sure. But you're the master of your own destiny, you do it on your time. You never see Ganon destroy the world until Link rocks up, do you?
So you may have been in such a hurry that you didn't notice an NPC was possessed by something that doesn't look right. Your ears might not have picked up some very deliberate foreshadowing in a particular song choice in a certain game about time travel and paradoxes.
Even on a smaller scale, you may not have tried exploring your nasal passage with something not designed for that purpose. Or helped yourself to a bottle of wine just to mess about with an artist.
It just goes to show that some developers really do think of the little things, as these examples you might have missed will open your eyes up to.