Here's a little quiz I found online, which assures me that I only know when people are lying SOME of the time. Give it a try--can you tell a liar?
You Sometimes Know When Someone's Lying
You can spot a liar if the liar slips up, but you're not always aware of other people's dishonesty.
Eventually a liar will reveal himself, and you usually will figure out if you've been lied to.
However, someone could be duping you without you knowing it. So watch out for the telltale signs of lying!