An appraising look.

This technique is useful when meeting suspicious and negative people. After meeting someone's discouraging gaze (it's often a nonverbal cue), look into her/his eyes for a couple of seconds. Then look at her/his feet and back into eyes. After that, look away. This technique of "silent appraisal" demonstrates to the person that you do not perceive her/him as a threat, that is, you are not afraid of her/him. Yet you had better stand up straight and behave confidently.