Little red riding hood went to the shop and bought an apple, what did red riding hood buy?

• Surely this is some sort of a trick question.
• I don't think red riding hood had apples in her basket she had pastries and butter.
• Aha, little red riding hood bought an apple but red riding hood bought something else.

We may not talk about apples so often in our physics classes (actually I do) but we do tell a lot of stories and then ask students a question about the story to see if 1, they were listening and 2, they understood what we said. The questions are often obvious (or so we think) but the response is often blank and the reason for this (I think) is similar to the little red riding hood situation. Students can't believe that we would ask such obvious questions, physics is supposed to be difficult isn't it? Students have often heard the story before but maybe don't remember it correctly or it was a different version. Rather than listening to this new version they try to remember what they learnt in the past.