I really have trouble with crowds and people I don't know touching me, shouldering me, walking up really closely behind me, etc. With horses, when the horse has a tendency to crowd you, you can swing the end of the lead rope back and forth and if they get in your space, it hits them. It works really well, so I have started doing that with my bags when shopping. Pick one with nothing breakable in it and swing it back and forth as I walk to force people out of my space. Looks like I am just idly swinging packages when in reality I am semi-deliberately hitting people who cannot ****ing maintain decent personal space.