Social engineering is the main way a hacker gets any information from their victims. People will talk you into doing/Telling something you may not want to, but may have too.
Hackers usually use social engineering because its one of the easiest ways to get information.
I personally love social engineering, aslong as you take a realistic approach to it, you also need to know your victim before you even try.
For example:
I recently tricked/Socialed a girl into taking her clothes off for me on Webcam (LMFAO), By creating fake programs, and proper wording i befriended her, slipped in a program that stated that she had some viruses on her computer, then said, the only way to remove the viruses, is if she were to take her clothes off (Still LMFAO), Of course the viruses were fake, but it was still a fun experience (In my opinion).