But don’t become too wedded to one interpretation of an action. Sometimes a person may twiddle a button because he or she feels nervous or inadequate and has no evil intent. I often bounce my knee up and down while sitting because it comforts me. I’ve heard cops conclude that when a person looks off to the right when describing an event it means they are lying, yet I look off to the right when telling the truth but am replaying the event in my mind and trying for accuracy.

There are body language hints to be read, but don’t rely too much on self-appointed gurus who say that X action must mean Y thinking.

Bugs Bunny: "I speak softly, but I carry a big stick."
Yosemite Sam: "Oh yeah? Well I speak LOUD! and I carry a BIGGER stick! and I use it, too!" BAM!