When some folks don't understand a question they don't ask for clarification . They assume it's the fault of the Questioner. They never assume it's their fault for not getting it. Why?

Because it takes some growing up to admit "I don't know". When you tell a child something he didn't know, he doesn't say "I didn't know that." He says "No it's not."

As a teacher it WAS my fault. It was my job to ensure they did understand. I told them early on to let me know if they don't.