One way to shop, is to start at the other end of the store if you can, that way you pass others only briefly. The first time the security man suggested this, it threw my list into disarray, and I had to read it upside down, which is a bit awkward when you get to the spuds at the end, instead of the beginning...
I do find though, that I almost stop breathing when I pass someone else, which makes the strangled 'gasp' at the end of the aisle a bit scary for the stackers...