-If I had a camera, I said, I'd take a picture of you every day. That way I'd remember how you looked every single day of your life.

-I look exactly the same.

-No, you don't. You're changing all the time. Every day a tiny bit. If I could, I'd keep a record of it all.

-If you're so smart, how did I change today?

-You got a fraction of a millimeter taller, for one thing. Your hair grew a fraction of a millimeter longer. You got a little happier and also a little sadder.

-Meaning they cancel each other out, leaving me exactly the same.

-Not at all. The fact that you got a little happier today doesn't change the fact that you also become a little sadder. Every day you become a little more of both, which means that right now, at this exact moment, you're the happiest and the saddest you've ever been in your whole life.

-How do you know?

-Think about it. Have you ever been happier or sadder than right now, lying here in this grass?

-I guess not. No.

-And have you ever been sadder?

-No...  What about you? Are you the happiest and saddest right now that you've ever been?

-Of course I am.

-Why?

-Because nothing makes me happier and nothing makes me sadder than you .

― Nicole Krauss, The History of Love