Before I retired, my job entailed me to meet many people from all parts of the world and mainly in top corporate roles, sheiks, oil czars, etc. I being a friendly sort of person, after a while, was able to discern whether the handshake or greeting was a warm, friendly one, in which case we would chat about anything but work, or a cold, piss-off type of handshake, in which then I would just go on my way. First impressions are very important.