I showed up at a temp assignment and had to immediately turn down the assignment due to the type and volume of the noise. It was a bottling plant. By the time I reached the guy I was supposed to report to, I was in extreme pain, and was ready to scream. I managed not to, and made it out of the place, but the man was mad because I left him short a worker. I understand his feelings, and I'm sorry I had to do that, but there was no way I could work there.
I think your best bet is to finish your errand as quickly as possible, and get outside. It is best to go at a slow time of day for the store, so you won't be stuck behind too many people at the check out counter. You could also try keeping your eyes only partly open to lessen the visual input.
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If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau