My sister had a final exam at school that she didn't feel prepared to do so I asked what she was able to do if I could postpone the exam a few days. She thought I was joking so she said anything, she would give me anything. I went out and talked to a friend who works at the school and asked him to turn off the central heating in my sister's classroom and say it was broken and he needed a couple of days to get it fixed. When I got back home my sister already had received a call from school saying the exam was postpone and I got everything what I wanted from her...