Do you give back BORROWED things?

My friends usually borrow CDs from me. Sometimes at school they borrow pen, pencil or anything else but they do not have the manners and the habit of giving back me the borrowed things. It makes me think were they taught any manners by their parents or there household is like this. But nonetheless if I ask them for my things they say, " Ok, I will give you back, what's the hurry for?" Well, what can I do then? Do you give things that you borrow, back to the owner?