Why are some things, like coffee, good every day without variation? I never tire of a strong, fragrant, steaming mug of morning deliciousness. It will lure me out of bed even if there is no reason I need to get up early.
Other things, however, like jokes and like some other experiences, are only good on first impression. The second time you hear them or encounter them they lose the funny and the joy. This may be because they rely on surprise, novelty, unexpectedness. Once you see them coming, they disappear into the mist or flop flat on the deck like a fish without air.
Living with you, my dear, is good every day. The good that you are does not rely on newness or on my not having encountered the same sort of goodness in you yesterday. I am always glad for your unchangingness. I am always glad to see your same face on the grey pillow next to mine in the morning. I am always glad for your solid presence next to my morning crossword. I am always glad for your nearness at the joyous receiving of good news and difficult receiving of bad news.
Frost was wrong: Some kinds of gold do stay.