SEing is the act of controlling people so that they give up confidential information. The different types of data these people are seeking can vary, but when citizens are targeted the “artists” are often trying to trick you into handing them your passwords or credit card information, or access your desktop to secretly install malicious software–that will give them access to your passkey and bank information as well as giving the hacker control over your laptop.
“Artists” use SEing skills because it is usually easy to fool your natural inclination to believe someone than it is to discover ways to hack your software. For instance, it is much easier to trick someone into giving you their passkey than it is for you to try cracking their passkey.
Defense is all about knowing who to trust. Knowing when not to, and when to believe a person; when to trust that the people you are chatting with is really the person you think you are chatting with; when to see that a website is or isn’t legitimate; when to believe that the people on the phone is or isn’t legitimate; when providing your data is or isn’t a smart idea, intelligent idea.
Ask any security professional and they will all tell you you that the smallest link in the protection chain is the human who accepts a person or scenario at face value. Social Engineering Forums is very informative about how to stay safe from being a victim of Social Engineering.