I never let tantrums stand between me and my groceries
However, neither do I accept that it's an inevitable part of being a toddler. In fact, I would do that 'nose to nose hiss' thing inherited from my mother. It's when you get them out of the car in the supermarket car-park, bend down so that you're face to face with them, and then say in the most menacing stage hiss you can muster if you so much as think about showing me up in there, I will come down on you like a ton of bricks... Scare the bejeezers out of the little poppet.
Ignore stares. You don't know what people are thinking so leave telepathy to the stage magicians.