Stolen wig

Charlotte stormed into the eye surgeon's office and went up to the desk. "Someone stole my wig while I was having surgery yesterday" she complained.

The doctor came out and tried to calm her down. "I assure you that no one on my staff would have done such a thing" he said. "Why do you think it was stolen here?"

"Well, after the operation, I noticed the wig I was wearing was cheap-looking and ugly".

"I think" explained the surgeon gently

Spoiler:

"that means your cataract operation was a success