[That's not affection, but an anti-meddling measure.]

Let me put it this way: the Space-Time Witch's Shop is between worlds, and Avalon exists on a layer of reality separated from the one you came from. The time difference may not be strictly equivalent - indeed, when you step out of the Shop, the world you were in might not have moved on in any significant manner.

[The more important question, really, is how Watanuki will reconcile the person he'll become to the one he was. Returning to the place of one's origin isn't always coming home.]