I believe if you can approach someone and grasp their hand firmly, like you're convicted to them, then it is not what you learn from them, but what they learn of you that makes a good handshake. Impressions, if you will. A weak handshake would indicate unwillingness to grip another's hand, however, to show that you are not afraid to clench someone's hand as firmly as possible. A handshake like that demands respect and obedience; trust.