Naturally, the success of these lines depends a lot on your delivery. Some of them require an ironic tone, some call for enthusiasm, some an air of puzzlement. Some of them will suit you better than others. Select the ones that seem most like something you would say, and remember that you can always alter them slightly to fit your own style. But don't be afraid to try something daring once in a while. It's not going to kill you, and it may slay them!