I accidently sent some private photos to a mate, realized my mistake and deleted them. Message was deleted in less than 10 minutes. The message had not even been delivered. I didn't see an option to delete messages for everyone so I thought that it will automatically do that. It didn't. Next day he was asking about the photo. I thought he was joking. He later forwarded me my own photos. Imagine my horror. He later forwards it to a group with my name below it. Social life ruined.