She was wearing roller skates.
Hop couldn't bring himself to look her in the eye, so he looked at the ground instead and that was a mistake because she was wearing roller skates and of course she was; she knew how he felt about them. Hop knew calculations. He could see the careful arithmetic in everything she did, in all of her choices down to her footwear, optimized to make him miserable.
The worst part was that he was living out a childhood dream of his. Traveling the world. Bringing justice everywhere he went. Overcoming the fantastic upset offered by a dastardly rival. He had become his favorite fictional hero.
But he had dreamed of gentler things, too, and those had been lost. Half-melted popsicles and sharing secrets. He had wanted to love her once, but now he knew he never would.