The thing is that she doesn’t see the world the same way everyone else does; where someone else will look at another person and say ah, he’s on his way to school, what she sees is
a shortcut that takes him right to the girl he will love all his life
(though there’s nothing to say she will love him; after all, perhaps she’ll turn her head at the last moment and see her own fate walk past)
inattention at a traffic light that will lead to an accident
(possibly fatal, in fact, if the doctor on attending decides to become distracted by another patient’s readings; or will possibly come through just fine)
walking through a lost ghost that will occur a vicious grudge
(the lost don’t always understand that they no longer belong here and sometimes even those who do will not willingly go)
and so on
and so forth.
All of them are inevitable fates and all of them are unchangeable choices. As one version of events plays in such a way, another will pull into a different path, until it all spiderwebs out to infinity. This is what she sees, and she is very good at figuring out exactly which thread she will witness directly — once you’ve had some practice, it’s practically second nature: his footsteps hesitate a moment, his head turns away briefly, the sight of the graveyard does not make him falter.
Conversely, though, her path has always been clear. Once one becomes aware of the inevitable, nothing comes as a surprise. If people could only learn that, there would be very little need for her shop indeed!
She puts her hand into Watanuki’s hair as he sleeps, and her hand is milk-white as the moon in contrast; she looks at him and she can see the broken strings and broken edges sweeping away, reknitting themselves in some places and withering to nothing in others. His own road shall never be as straightforward as hers, but that is how it should be: only Watanuki can be exactly like Watanuki, and there is no other of her, so only she can be herself.
And she can watch as he triggers inevitability after inevitability, which will take him to where he absolutely must go, and she can perhaps nudge him here and there in return for the little extra favors he does for her, but she will do no more than that. Certain rules even she cannot break, though she sees the twists in the road ahead and the places where he will falter and he will fall.
Things are more fun that way, though, she thinks, and wasn’t that what you thought as well, Clow Reed?
The wind moves through her hair and gives her no other answer.