If the person you're waiting for happens to be waiting for you too, then what you're waiting for isn't a person, but a missed connection.
Later, Qiu Sheng realized that all along, he had simply been following in Xia Sheng's footsteps, one step at a time. Yet he had also found his own way and become a better Qiu Sheng.
Later, Xia Sheng realized that all along, he had been pausing at every step, waiting for Qiu Sheng to draw near. The flowers blooming along the way were the most beautiful love letter of his life.
"I heard you're waiting for me."
"Yes, I'm waiting for you."
"What a coincidence. I'm waiting for you too."