Watanuki stops being a victim of circumstance the moment Yuuko decides to stop being patient with him. The show pivots from "strange customer, strange wish" filler into something with teeth, where every debt compounds and every answer about who he actually is costs him something he didn't know he was carrying. By the end, you understand that xxxHOLiC was never about the wishes, it was about a kid learning that wanting something and being willing to pay for it are two completely different things.
Watanuki continues working at Yuuko's shop, helping her customers while slowly earning the wish she promised to grant him: freedom from his ability to see spirits. At the shop, every request has a cost, and the price must match what is asked for. When certain facts about his everyday life come to light, he lands in more trouble than he can manage and learns Yuuko's lessons the hard way. His classmates Doumeki and Himawari are drawn into the misfortunes that follow the shop's clients and his own circle. The tone moves between comedy and psychological, supernatural unease.