the art of manipulating people

Social engineering is the art of manipulating people so they give up confidential information. The types of information these criminals are seeking can vary, but when individuals are targeted the criminals are usually trying to trick you into giving them your passwords or bank information, or access your computer to secretly install malicious software - that will give them access to your passwords and bank information as well as giving them control over your computer.

Explain a scenario where you or someone you know may have unknowingly given too much personal information to a stranger. How could this situation  been avoided?