This person understood the concept of mirrors. Life mirrors back to us what is most helpful for us in that moment. Sometimes it's an area in us that needs healing, and so our buttons get pushed (buttons are a good thing...). Other times, it's an area in us that's beautiful.
We love people who brings out the beauty in us. They are reflecting back to us what we love about ourselves, and that magnifies and strengthens those qualities in us, which, in turn, we express more of and attract more of. This is already a beautiful thing. But what also happens is that the more we are around people who reflect back our beauty, the more we start to appreciate ourselves, because the more we are ourselves expressing those qualities we love in them.
And then something even more magical happens. The more you around someone who is reflecting back your beauty, and the more you start to appreciate that beauty in yourself, the more you start to appreciate the gift those buttons (remember those buttons?) offer you. The same letter continues:
"...I would change nothing about you, ever. I love your good moods and your bad ones. I love your joy and your frustration. I love your tenderness and your irritability. I love all of you. I love you when you're awake and when you're tired..."
What, for you, is love? Who in your life is reflecting back your beauty, and who is pushing your buttons? And what is the gift for you beneath each?