Every time you meet someone new you've got an interesting job to do: analyze that person. One might ask: "how do you actually do that? Do you need some special type of scan?" No, actually you don't. There're multiple details telling you the story of that person: including body language, posture, tone of voice... and even handshake!
For example, do you know what a "glove handshake" is? In fact, the person giving you such a handshake can be characterized as trustworthy. Meanwhile, the person who puts his/her hand on top of a handshake is trying to show you who's the boss. So a handshake isn't that simple.