When you are asked to provide "thought-provoking questions" for an assignment, the most important thing is for those questions to come from you. I would suggest rereading the story carefully and marking thoughts, ideas, and even questions in the margin. If you can't write in your book, you can use post-it notes or even little pieces of note paper as you read. Start by asking questions at certain places, such as "Why does he think this?" "Why does he react this way?" "What would I do in his place?" Keep in mind that Dade, the sensitive narrator, is recalling how he disappointed his parents and himself when he turned 18.
Thought-provoking questions could deal with the disappointment of the parents ("Why were they disappointed?" "Were they right to be disappointed?") or Dade's developing feelings about the shoplifter ("Why does he let her go?" "Why does he think about her needs instead of understanding the business needs of the store?")
The most thought-provoking questions will be those that help you to think more deeply about the character development and conflict in the story. Good luck.
The summary and analysis of the story available on E-Notes might help you with your questions, too.