1) Scanning - When bad guys scan the area, their chin is down They tend to look around using quick, jerky movements. If you meet their eyes they will immediately avert their gaze.
2) Clinched Fist
3) Fidgety
4) A Bladed Stance
5) Target Fixation
6) Pretending To Look Busy
7) Change In Demeanor
8) Attempt To Cover Face
Any single threat indicator might not mean anything but when more than one is viewed together the likelihood you are dealing with someone out to cause you ill will goes up.
See:
Left of Bang
