I've experienced moments like that. For example, last night Sam and I went out to see the harvest moon. Walking up the road towards the open field, Sam was scared of the dark, so I picked him up and carried him in my arms. When we saw the moon, it was so bright, it cast our shadows on the ground. We both just stood there and watched it for a while.
I'm a wordy, rambling person (I'm sure you've noticed) and I wouldn't dare try to express such a moment as a haiku. But I liked this one, written over 200 years ago by a Japanese gentleman-poet:
Such a moon -
Even the thief
pauses to sing.